The warrior forums have many conversations on sampire builds. Also I have read the UOguide sampire build which is very dated.
Hi :) I returned 3 months ago after 15 years and we know, everything changed :) I tried to update my chars to the modern times but I feel I still miss something, that I don't know or understand. My sampire actually can handle lots of stuff solo but there are still some mobs that instakills me...
community.stratics.com
I like to think of cheap ways to reach a high level and I think a mace samp might be one of the best ways to get everything you need and not break the bank. I think the most budget friendly weapon combo is a black staff for whirl wind and a spear for armor ignore. Very solid base damage...
community.stratics.com
This one is more of end game builds for sampires,
Modern Sampire
There are many more if you dig deeper , but once you start building you can ask questions in the warrior forum and many who responded to these will impart knowledge for you as well.
PvP I have no idea.
UO Spellcaster the spell caster forums also has builds. If you need specifics one could post and get answers. Mage/Mystic/Spellweaver is very popular for PvE and there are variations on this build. Rising Colossus from Mystic skill at 120 skill with 120 focus is very powerful for a summonable tank that takes five slots.