Rmemebr that
most computers run off 5V and maybe 12V. You don't need that
many dummy loads!. An assortment of car bulbs (and holders if you don't
want to solder wires driectly to the bulb caps) is a good start.
That is only true about TTL and computers that used a Z80 or later designed
chips.
DTL also uses +5V IIRC. And (equally IIRC) the 8080 used some subest of
+/-12V, +/-5V. 12V bulbs are common, 6V ones will do for the 5V rails.
Going back even further, I guess 15V rails were quite usual. Perhaps 3 6V
bulbs in series would do for those if you can't find 15V bulbs anywhere
or find suitable resistors.
-tony