There's no "best" starter

Every Partner Digimon in Digimon UP has the same stats and the same skill at the start. So pick the one you most want to look at all game — Agumon, Gabumon, Renamon, Guilmon, whoever.

What actually matters

  • At Level 20 you choose a Battle Type — Attack, Defense or SP. This determines your active and passive skills. SP (Recovery) is the current meta pick.
  • You can't unlock a second Partner until your first reaches Lv.99 / Mega, so you'll be with your pick for a while.

Browse all 15 on the Partner Digimon page, or see How to Change Battle Type.