I have seen many themes suggested already, ranging from +1/+1 counters (similar to Experiment KrajExperiment Kraj) to the -1/-1 counters theme (similar to Hapatra, Vizier of PoisonsHapatra, Vizier of Poisons), and even a CloneClone and Shapeshifter theme, just playing weak creatures with beneficial abilities that become absurd when transferred onto Volrath's 7/5 body
Underrated cards in MTG The Brothers' War Raze to the Ground - 6.9 It looks like your typical naff artifact removal card, but in this set you'll always have a decent target, and the first one of these in your deck will kill the best creature on board much of the time
Theyve done almost all the design work for you, after all
Early cards, prize cards distributed at events and contests, and cards in strong condition that have received high grades from third party authentication services are attracting attention not only for nostalgia, but also for their cultural and asset value