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I'm currently developing Poketrader (name subject to change due to similar sites). Pokeportfolio / Pokeinvestor / Pokefolio / Pokemarketcap / Pokefolder could be good names as well.
It's a site similar to coinmarketcap, but instead of cryptos/stocks you have Pokemon cards. Every card has their market value shown in real time and charted so you can check their price development over time.
You can create an account and make your own portfolio and see how much your entire collection is worth without having to keep a manual list on your computer.
I realize Pokellector is almost like this, and TCGplayer is almost like this as well. But neither of them really gives you everything you want.