Everything past FX series has DX9 support (exept low end 9000 series Radeons).
List of interesting cards... OK - here's NV :
1) FX 5800 Ultra because it's THE leaf blower
2) FX 5950 Ultra because it's best FX card (best of worst)
2) 6800 Ultra AGP/PCI-e first DX9c card + has official 98 support (last high end native AGP)
3a) 7900 GTX, best DX9c only card from NV (with unofficial 98 SE support)
3b) 7900 GS*/GT AGP, fastest AGP card from NV (*depending on model can be moded to GT) also one Galaxy model "supports" AGP 3,3V : LINK. There are 7600/7300 series cards with AGP 3,3V support as well.
4) 8800 GTX/Ultra, it's legendary (duh), first DirectX 10 card 😀
5) GTX 285, fastest single GPU DirectX 10 only card
6) GTX 480, who doesn't like that grill on top 😁
7) GTX 580, fastest GPU that can be mounted on not that good PCI-e 1.x boards (best first gen DX11 GPU with DX11 and DX12 [FL_11.0] support, example for that DX12 : LINK).
8 ) GT 610 newest PCI (non-e) card
9) GTX 780 Ti, best Kepler (not counting GTX Titan Black) and best official Win XP card from NV
10) GTX 750 (Ti), a good thing to have as "plan B".
Maxwell 2.0 and Pascals aren't that interesting to me at this point.
ATI/AMD :
1) 9800 XT (best DX9a card)
2) X850 XT PE (best DX9b card)
3) X1950 Pro (best perf/$ AGP card with good compatibility)
4) X1950 XTX best DX9c only card (overall) + first GDDR4 😀
5) HD2900 XT first DX10 ATI card
6) HD 3850 AGP, fastest AGP card
7) HD 4670 AGP, newest AGP card
8 ) HD 4870 first GDDR5 card
9) HD 4890 "1GHz", fastest DX10 card from ATI
10) HD 5870 first DX11 card (overall), great DX9/10 performance. Fastest single GPU card from ATI/AMD for PCI-e 1.x systems that can't work with PCI-e 3.0 cards.
11) HD 7970 first GCN card (really good even today thanks to 3GB/384bit VRAM)
12) R9 290X first DirectX 12 (FL_12.0) card
13) R9 Fury (X), first HBM card
I skipped cards that were "unusual" (like Gigabyte 3D1-68GT), and all multi GPU cards.