I currently have six credit cards and feel like maybe I could reduce the number.

• a B of A mastercard that I have had in one form or another since 2000, when it was an MBNA University of Illinois MC I signed up for on the quad and got a free t-shirt. It sits in a drawer and I almost never use it. I basically keep it now because it's my oldest card and my only Mastercard. Turns out the gas company will only let me pay by credit card if it's a MasterCard, but I just have them deduct from my checking account anyway. No annual fee. Does charge foreign transaction fees.
• a PenFed cash rewards Visa that I got in 2008. I got it because it pays 5% cash back for gas paid at the pump, but I only rarely drive these days and almost never need to get gas (Mr Gfunk is the main driver and takes the car to the office 1-3x/week). No annual fee, no foreign transaction fees. Low credit limit too, only about $5000.
• an Amex Marriott Bonvoy card that I got in 2004. Used to be the SPG Amex. I keep it in a drawer and use it for Marriott stays and for the free night annually. I think the AF is around $95. No foreign transaction fees.
• a Chase United Explorer card that I mostly use when overseas and for buying plane tickets on UA. $95 annual fee and includes 2 annual UA Club passes, which I generally use. No foreign transaction fees. Open a little over a year, since I moved to Chicago and started flying mainly UA. I wanted the free checked bag and group 2 boarding, but now I'm Silver and get those anyway. Don't know if I will remain Silver, though. And I do like the discount on in flight purchases.
• a Chase Freedom Unlimited. Used to be my daily "personal" card since I can combine UR points with our CSR card and can transfer to a variety of places. No annual fee but does charge foreign transaction fees. Open since 2018 or so, or whenever the SPG Amex got converted to the Marriott one.
• a Chase Sapphire Reserve. This is the card Mr Gfunk and I put all our shared expenses on. When there are enough points available I'll either buy travel on the UR portal or transfer points to partners for hotel stays/mileage award tickets. $550 AF but I feel it's adequately offset by the card's other benefits, what with the $300 travel credit, reimbursement for Global Entry fee, various travel insurances, etc. Open since 2016.

What are peoples' thoughts? Get rid of one or two or just keep them in a drawer like I've been doing? I always pay the full balance every month, so I don't even know what the cards' APRs are, and it doesn't matter to me in any case.