I see two ways to answer this question, the most important relics and the most impactful relics. To me the most important relics would be arena/crystal income focused, while the impactful relics are characters who are most improved with relics (probably better from the GAC/TW/TB perspective).
Most important: GAS, 5s, Echo, Arc, GK , JKA, Ahsoka, GG, B1, Bossk
for this I went with the 501st (best arena team at equal relics) leaving out rex who is least important. The rest are ships and/or requirements for GAS. Bossk is on there because of his ship as it has been the best option in like every meta since its release.
Most impactful: GAS, 5s, GK, JKA, GG, Han, Darth Revan , Malak
Most of these are self explanatory and in no particular order. DR is probably least important since it is mostly for speed imo. I stopped at 8 because the next group is hard to differentiate to me: GBA, Spy, Spirit, JKR, Yoda, Chewie, Fallen Bastila, Echo, HK
Replies
5s and GAS make that team and are more important than the other clones.
Malak better than DR.
Spirit and Spy completely change those teams.
They're my top ones
Most important: GAS, 5s, Echo, Arc, GK , JKA, Ahsoka, GG, B1, Bossk
for this I went with the 501st (best arena team at equal relics) leaving out rex who is least important. The rest are ships and/or requirements for GAS. Bossk is on there because of his ship as it has been the best option in like every meta since its release.
Most impactful: GAS, 5s, GK, JKA, GG, Han, Darth Revan , Malak
Most of these are self explanatory and in no particular order. DR is probably least important since it is mostly for speed imo. I stopped at 8 because the next group is hard to differentiate to me: GBA, Spy, Spirit, JKR, Yoda, Chewie, Fallen Bastila, Echo, HK
JTR
R2
Both Kylos
JKA
Padme
GK
Finn and Snips and next, followed by Embo and FOE/X