As seat and configuration questions are common in this forum I thought I should put together an overview with all the different seat configurations and products found on the various aircraft in the THAI fleet.

The information is presented in the following way:
Aircraft type (Numbers of aircraft) Registration Seat map
Class (Number of seats) Configuration Seat type In-flight entertainment/power/seat features Link to picture of seat/cabin

Airbus 330 (15)

NB! All the old A330's with recliner seats have been retired. The entire A330 fleet now have the 2nd generation angle-lie flat seats in Business class and AVOD in both classes.

Airbus A330-300 (8) HS-TEN to -TEU Seat map
Also referred to as: 330, 3303, Airbus Industrie A330, «RR A330»

Royal Silk (36) 2-2-2 2nd gen angle flat PTV AVOD AC View
Economy (263) 2-4-2 Standard PTV AVOD AC View

Notes:
*Previous gen entertainment system. Economy seats differ from -TBA to -TBG aircraft.
*These aircraft are powered by Rolls Royce engines.

Aircraft were delivered between 1st Apr 2009 and 30th Mar 2010.

Airbus A330-300 (7) HS-TBA to -TBG Seat map
Also referred to as: 33H, 3304, Airbus Industrie A330, «RR A330»

Royal Silk (36) 2-2-2 2nd gen angle flat PTV AVOD AC USB Wifi View
Economy (263) 2-4-2 Standard PTV AVOD AC USB Wifi View

Notes:
*Newest gen entertainment system. Economy seats differ from -TEN to -TEU aircraft.
*Same Economy seats as installed on Airbus A380-800 and Boeing 777-300ER.
*These aircraft are powered by Rolls Royce engines.
*Wifi available for a fee: 3MB $4.50; 10MB $14.50; 20MB $28.50.

Aircraft were delivered between 16th Nov 2011 and 22nd Apr 2013.

More data about the A330 fleet available here.

Airbus 350 (7)

Airbus A350-900 (7) HS-THB and -THH Seat map
Also referred to as: 359, 3591, Airbus Industrie A350-900

Royal Silk (32) 1-2-1 Full-flat PTV AVOD AC USB Wifi View
Economy (289) 2-4-2 Standard PTV AVOD AC USB Wifi View

Notes:
*Royal Silk Class is the same type as on B777-300ER and A380-800, with only difference being seat finishes and seat width due to aircraft type.
*Wifi available for a fee: 3MB $4.50; 10MB $14.50; 20MB $28.50.

Aircraft were delivered between Aug 2016 and Sep 2017.

Airbus A380 (6)

Airbus A380-800 (6) HS-TUA to -TUF Seat map
Also referred to as: A380, 3801, Airbus Industrie A380, A388

Royal First (12) 1-2-1 Full flat «suites» PTV AVOD AC USB Wifi View 1 View 2
Royal Silk (60) 1-2-1 Full flat «staggered» PTV AVOD AC USB Wifi View 1 View 2
Economy (Main deck: 377, Upper deck: 58) Main deck: 3-4-3, Upper deck: 2-4-2 Standard PTV AVOD AC USB Wifi View

Aircraft were delivered between 26th Sep 2012 and 29th Nov 2013. More data about the A380 fleet available here.

Notes:
*Wifi available for a fee: 3MB $4.50; 10MB $14.50; 20MB $28.50.

Airbus A320 (20) (All aircraft operated by Thai Smile)

Airbus A320-200 (20) HS-TXA to TXH and HS-TXJ to TXU Seat map
Also referred to as: 3202

Economy (180) 3-3 Standard

Notes
*HS-TXH and newer aircraft have sharklets (winglets)

Aircraft were delivered between 29th Jun 2012 and 5th Nov 2015.

Boeing 777 (34)

Boeing 777-200 (6) HS-TJA to -TJD and -TJG to -TJH Seat map
Also referred to as: 777, 7724, Boeing 777-200/300

Royal Silk (30) 2-2-2 1st gen angle flat PTV AVOD AC View
Economy (279) 3-3-3 Standard PTV AVOD AC View

Notes:
*Not all aircraft have been refitted with PTV AVOD AC in Economy.
*All aircraft have the 1st gen angle flat seats installed in Royal Silk.

Aircraft were delivered between 31st Mar 1996 and 9th Jan 1998.

Boeing 777-200ER (6) HS-TJR to -TJW Seat map
Also referred to as: 77E, 77E1, Boeing 777-200/300

Royal Silk (30) 2-2-2 2nd gen angle flat PTV AVOD AC View
Economy (292) 3-3-3 Standard PTV AVOD AC View

Aircraft were delivered between 1st Nov 2006 and 29 Oct 2007.

Boeing 777-300 (6) HS -TKA to -TKF Seat map
Also referred to as: 77R, 7732, 773, Boeing 777-200/300, Boeing 777-300

Royal Silk (34) First row: 2-2-2 Other rows: 2-3-2 2nd gen angle flat PTV AVOD AC USB View
Economy (330) 3-3-3 Standard PTV AVOD AC View

Aircraft were delivered between 23rd Dec 1998 and 9th Dec 2000.

Boeing 777-300ER (14) HS-TKK to -TKR and -TKU to -TKZ Seat map
Also referred to as: 77B, 74B1, 77W, Boeing 777-300

Royal Silk (46) 1-2-1 Full flat «staggered» PTV AVOD AC USB View
Economy (306) 3-3-3 Standard PTV AVOD AC USB View

Note:
*Some aircraft have different seat colors and interior finishes, but the configuration and seat types are unchanged.
*On flights to ARN and CPH the second Royal Silk cabin (after door L2/R2) is sold as Premium Economy.

Aircraft were delivered between 2nd Aug 2012 and 28th Sep 2015. More data about the 777 fleet available here.

Boeing 787 (8)

Boeing 787-8 (6) HS-TQA and -TQF Seat map

Royal Silk (24) 2-2-2 Full flat PTV AVOD AC View
Economy (240) 3-3-3 Standard PTV AVOD AC View

Notes:
*The 787-8 features a new type of full flat business class seat, similar to United Airlines' (Continental version) BusinessFirst seat.

Aircraft were delivered between 16th Jul 2014 and 7th Aug 2015. More data about the 787 fleet available here.

Boeing 787-9 (2) HS-TWA and -TWB Seat map not avail

Royal Silk (30) 1-2-1 Full flat PTV AVOD AC
Economy (268) 3-3-3 Standard PTV AVOD AC Notes:
*The 787-9 features the reverse herringbone seat (similar to Cathay Pacific) in Business class, which is different from the seats in the 787-8s.
Aircraft were delivered between Sep 2017 and Oct 2017. More data about the 787 fleet available here.

Boeing 747 (10)
Boeing 747-400 (5) HS-TGO, P, W and X Seat map
Also referred to as: 74R, 7443, Boeing 747-400, «10F»

Royal First (10) First row: 1-1, second and third row: 1-2-1 Full flat «pods» PTV AVOD AC View
Royal Silk (Main deck: 14, Upper deck: 26) 2-2 1st gen angle flat PTV AVOD AC View 1 View 2
Economy (325) 3-4-3 Standard PTV AVOD AC View
Aircraft were delivered between 20th Oct 1993 and 12th Nov 1997.

Boeing 747-400 (6) HS-TGA, B, F, G, Y and Z No seat map available
Also referred to as: 74N, Boeing 747 All series, «9F»
Royal First (9) First row: 1-1, second row: 1-1-1 and third row: 1-2-1 Full flat «suites» PTV AVOD AC USB View 1 View 2
Royal Silk (Main deck: 14, Upper deck: 26) 2-2 2nd gen angle flat PTV AVOD AC USB
Economy (325) 3-4-3 Standard PTV AVOD AC USB View

Notes:
*All aircraft with old recliner seats in Royal First, aka the inferior «14F», have been reconfigured to the new «9F».
Aircraft were delivered between 22nd Dec 1997 and 4th Nov 2003. More data about the 747 fleet available here.

Boeing 737 (2)

Boeing 737-400 (2) HS-TDD and G Seat map
Also referred to as: 734, 7341, Boeing 737-400

Royal Silk (12) 2-2 Recliner View
Economy (137) 3-3 Standard View

Aircraft were delivered between 10th Jul 1992 and 6th Jan 1998. More data about the 737 fleet available here.

[B) NB! Aircraft types no longer in service. (Links to seat maps might be broken as aircraft are no longer listed on THAI's website)

[u]Airbus A300 (5) NB! Withdrawn from service

Last scheduled service was on 31st of July 2014.

Airbus A300-600 (5) HS-TAT and -TAW to -TAZ Seat map
Also referred to as: AB6, 36R1, Airbus Industrie A300-600/600C

Royal Silk (46) 2-2-2 Recliner Overhead/bulkhead/projector View
Economy (201) 2-4-2 Standard Overhead/bulkhead/projector View

Aircraft were delivered between 30th Nov 1998 and 15th Dec 1998. More data about the A300 fleet available here.

Airbus A340 (6) NB! Withdrawn from service

Airbus A340-600 (6) HS-TNA to -TNF Seat map
Also referred to as: 346, 3461, Airbus Industrie A340-600

Royal First (8) 1-2-1 Full flat «pods» PTV AVOD AC View
Royal Silk (60) 2-2-2 1st gen angle flat PTV AVOD AC View
Economy (199) 2-4-2 Standard PTV AVOD AC View

Aircraft were delivered between 29th Jun 2005 and 29th Oct 2008. More data about the A340 fleet available here.

***
FAQ

Q: Which routes have full flat seats in Royal Silk?
A: Only the Airbus A380-800, A350-900, Boeing 777-300ER, 787-8 and 787-9 feature full flat seats in Royal Silk. The A380 is used on the following routes: LHR, CDG, FRA, HKG, KIX and NRT.
The B777-300ER regularly serves these destinations: OSL, CPH, ARN, FRA, BRU, ZRH, VIE, SIN, PVG, PEK, MEL and BNE. It also regularly flies domestic runs to HKT and CNX.

Q: Which routes get the new 747 «suites»?
A: Any route which is scheduled to be operated by a Boeing 747 might see the new «suites», but some routes are more likely to get them (but not guaranteed). These routes are: MUC, HKG, HND and SYD. Flights to HKT are often operated by the them, although these flights are without First class service.

Q: What are the chances of ending up on one of the old Boeing 747s with recliner seats in Royal First and Silk?
A: 0 %. All Boeing 747s have been converted and feature full flat seats in Royal First and angle flat seats in Royal Silk. Every seat in Economy also features a PTV with AVOD and AC power (every two seats).

Q: To which destinations do TG offer Royal First?
A: LHR, CDG, FRA, MUC, HKG, KIX, NRT, HND and SYD. Flights to PEK and PVG have "seasonal" (rather occasional) F service.

Q: Which version of the Boeing 777 features Royal First?
A: None. TG leased a handful of Boeing 777-300ERs from Indian Jet Airways a few years ago, that had eight enclosed first class suites. These aircraft have been returned to Jet Airways and are no longer in the fleet.

Q: Which destinations are served by wifi enabled planes?
A: Airbus A380 on routes to LHR, CDG, FRA, HKG, KIX, NRT. A330 (Only the 33H-version) on routes to PER, TPE, PVG, HKG, KIX, ICN and other intra Asian routes. A350 on routes to MEL.

***

All of the information above is based on seat maps from TG's own website and fleet information from planespotter(dot)com, as well as on information already available on this forum thanks to its dedicated members. Cabin views are from airliners(dot)net and jetphotos(dot)net.

Please feel free to comment if you have more information and if anything I've written is false. I appreciate all the help I can get.

And remember: There is always the possibility of being TG'ed (being subject to a last minute equipment change). Thus you never know which aircraft and configuration you will get until you actually set foot on the aircraft.

Happy flying!