An S3 Trio card will work with OpenVMS and almost certainly with
Debian, although the picture quality is fairly poor.
I have a PowerStorm 3D3O (ZLXp-E1) which will do 8 plane at 1280x1024.
I've not tried it in my AlphaServer 300 4/266 because I installed a
ZLXp-E2. I would recommend this card if you can find one - I got one
new from the USA for about $40.
Postage would depend on where you are in the world.
Regards,
Mark