Which Funko Pop figures are still holding their value?

With Funkos, it's like with a lot of collectibles - the market is pretty brutal. The figures that hold their value are mostly the older releases from the first couple of years (2010-2014), especially if they're still in OVP and were limited editions. Certain franchises like Game of Thrones, Marvel, or Disney have held up more stable than others. But honestly, a lot of the newer standard Pops are continuously losing value because they just keep getting reproduced all the time.

What really has staying power: exclusive variants (the ones that were only available at certain stores), chase versions, and figures of characters that have cult status now or are from discontinued series. OVP is basically a prerequisite - opened copies are pretty much unsellable at a better price. But even then you have to be realistic - some collector-focused series have held their values reasonably well, while mass-market stuff tends to decline.

Best advice: if you want to speculate, you need current info from the collector market, not just random listings. On sites like PopPriceguide or in relevant communities, you'll get a better sense of what's moving. Generally, I wouldn't expect to get rich off this - it's more for people who enjoy the collecting aspect, not for investing money.