Also some thoughts on planning for anyone else who plans to do this, and massive shout to all those who have been discussing deals. Thought I would put it together in one place, and perhaps we should expand the scope of the wiki post! I think I could get it to around $2500 but that is just flights, and would love to get some help once I am further along! Here are some thoughts in the meantime:

Europe to Asia

SV is pretty good between MXP-SIN/KUL/CGK/CAN/BJS, GVA-SIN, plus AUH-MNL for those who can fly Wizz into AUH from Europe. Otherwise Middle East/Europe to Egypt is a good substitute.

Turkmenistan Airlines T5 is super cheap for those who just need a ride. Need to book on official site.

MU has a lot of good return fares to Asia from London.

Asia to Europe

VN from CAN-Europe.

MU from ICN.

Europe to North America

SK Youth is a bargain.

OSL-USA can potentially get VS/AF/KL and potentially DL/SK in one fell swoop in about $400. Struggling on this and any help would be appreciated.

Alternatively, NCE to USA via LHR (NCE AF LHR VS USA DL EUR) does something similar at a higher cost.

Helpful 5th freedoms

CAN-BKK on KQ
KUL-CGK on KL
SIN-DPS on KL
SYD-AKL on MU

North America to Asia

Some SV fares at $400-500 such as IAD to BKK but not of interest to me so others could add to this!

Non qualifying fare classes

Many domestic flights on RO. Use international ones to or from OTP such as BUD/BEG/IST/SKG/ATH as a cheap fix.
Most reasonably priced MF flights in Economy do not qualify. But even the cheapest domestic business flights seem to. Trip.com via Google Flights is magical.

Good fares on Individual Airlines

Most domestic flights (Notably not KE)

KL 5th Freedoms
UX to and from PMI
GA on TKG v.v. CGK
KE to ICN - TSN/DLC/PEK/PVG/TSN, and reverse on some cases too
VN ICN-BKK/KUL and KUL/SIN to HKG, also helps with sidestepping visa requirements

Tools

Flightconnections.com
GCMap.com
Google Flights. Explore by selecting continent or countries and the map. Search a route to apply filters first, then choose a country to explore the map with filters.

Status

Those with status might want to match with Delta for a more comfortable trip, although using those benefits will be tricky.
There is currently a Star Alliance Status Match for Eurobonus members for those who are interested as well.

That's it for now! Thanks for reading!