You could ship them to me and I'll take care of them... heh.

Check out current eBay prices.

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Yes, I'd say about half of them are already worth to be taken good care of and the other half is very likely to gain value.

ATI 3850 AGP - interesting
Rage 128 Ultra AGP - not interesting
GeForce ti4200 64mb AGP - interesting
Dell Riva TNT 2 AGP - not interesting
Geforce 2 MX AGP - not interesting, but depends on particular model, cards with dual monitor support are fancy
Geforce 2 GTS AGP - interesting
asus v9999 6800gt AGP - interesting
GeForce 7900 GT PCIe - not interesing atm, but these cards are slowly dying out due to manufacturing plague
Radeon 5870 PCIe - interesting
Radeon 3870 PCIe - not interesting
GTX 480 PCIe - interesting
GTX 770 PCIe - not interesting, but keep in mind that we're living in a crazy world right now
GTS 250 PCIe - interesting
GTX Titan 6GB PCIe - interesting
Geforce 8800 GS PCIe - not interesting
GeForce 8800 GT PCIe - not interesting
GTX 590 PCIe - interesting

In these times of GPU shortage and high prices, the GTX 770 PCIE is a card you can use in a current system... Kepler (the architecture of that card) is just going legacy for the next major release.
The GTX Titan is another more powerful Kepler card
The GTX 590 is a fire breathing monster with a 365W TDP and DUAL Fermi GPU - it's like a pair of GTX 580's in SLI, but underclocked a bit
The GTX 480 is also a Fermi - driver support for Fermi ended some time back, but there are drivers for Win10 - with the notorious texture bug in Shadow of the Tomb Rader
The above are DX12 capable, with the outdated driver issues limiting the usefulness of Fermi in modern systems
The Radeon 5870 is also fairly powerful, but is limited to DX11 and on legacy drivers.

The lower spec PCIE cards are not very exiting, mostly useful for testing when you don't trust a system not to destroy an expensive card.

On the AGP side, the 6800GT is a powerful card, The Ti4200 is a DX8 classic, while the Geforce 2, 2MX and TNT2 are "bread and butter" cards of their era

it's like a pair of GTX 580's in SLI, but underclocked a bit

Overall it's slightly slower than GTX 480 SLI/GTX 570 SLI, with no headroom for overclock (unless blowing up VRM is your thing).

The above are DX12 capable, with the outdated driver issues limiting the usefulness of Fermi in modern systems

Main Fermi problem is lack of sufficient amount of VRAM today. Same goes for GTX 770, which only barely has enough with 2 gigs for minimal settings. Although 4 gig version is somewhat decent and should match 1050 Ti.

The Radeon 5870 is also fairly powerful

Nah, drivers aged horribly and 1 gig of VRAM is just as bad today or 5 years ago (hello Doom 2016). It's decent card for XP build though.