IMO, best cyclops based 3* team is probably Switch/Iron Fist/Cylops. Switch makes purple for IF, IF makes black for cyclops, cylcops kills things. Only downside of this team is that there is no active blue, and no defense.
This is probably one of the best 3* teams overall too.
Other rainbow Cyke variants include:
3* Cyclops/blue user with alternative red/purple and green user, examples:
Cyclops/Steve/GSBW - Steve’s red is usually much better. Slow team, however.
Cyclops/cMagneto/Kamala - cMagneto’s red meshes much better with Kamala’s purple
Cyclops/cMagneto/Scarlet Witch
Cyclops/cMagneto/Fist
Cyclops/She-Hulk/Kamala
Cyclops/Daredevil/Kamala - Daredevil’s red can be much, much more AP efficient especially if spammed in conjunction with Cyke’s yellow
Cyclops/Daredevil/Fist
Cyclops/Vision/Scarlet Witch - Vision’s red is easily better if he’s buffed, etc.
3* Cyclops/someone to feed black and/or red (as Cyke already feeds red to himself)/any good fitting third, examples:
Cyclops/Fist/Grocket
Cyclops/Fist/Beast
Cyclops/Doom/Patch
Cyclops/Doom/Thor
Cyclops/Loki/Beast - Loki feeds both with AP
Cyclops/Mystique/Patch, etc.
Mixed 2*/3*:
Cyclops/Patch/oBW
Cyclops/Ares/oBW
Cyclops/2* or 3* Thor/oBW,
Cyclops/cStorm/Magneto MN, etc.
Cyclops meshes badly with Black Panther, Cage, Hood, Colossus, Gamora, Punisher, Human Torch, etc. (significant colour overlap). Despite this, he’s good with Captain Marvel if she can tank over him and fuel red/black AP for Cyke as they have the exact same colour order of red/yellow/black. Cyke’s red and black are pretty much always better but Marvel’s black can be situationally better. The only third with fitting actives currently is Iceman, though, so you are going to miss some active colours if running Marvel/Cyclops as the core.