So I did a quick test to see what the abbriviations after UnD were in IGM in shortest number mode...
Turns out trillion and trigintillion use the same abbriviation (yes, trigintillion has a space inbetween the number and the T, and trillion doesn’t, but is that really enough to distinguish them?) Quadrillion and quadragintillion use the same abbriviation as well. (Qa for them). Same for quintillion and quinquagintillion, sextillion and sexagintillion, and septillion and septuagintillion. Octogintillion uses a plain O, which is SMALLER of an abbriviation than Oc, for a number so much bigger. Ditto for Nonagintillion using N. (Vigintillion doesn’t have these issues, it just uses V, for anyone wondering.)
Stuff like UnT and QaQa are fine, but there really should be abbriviations made for trigintillion, quadragintillion, quinquagintillion, and so on. Stuff like Tg, Qg, Qq, Sg, St, Og, Ng. Also we should get centillion and uncentillion, instead of just showing Inf. once it hits 1e303.