Xiao
Naga
Balance
Champ
Stinger

Lucky, Stinger, Xiao, Champ, and Naga should be the best team if we're talking about strength, skill, leadership, technique, and leadership+Luck. The others are better at mechanic like pink and gold or too in experience like green and skyblue.

Hammy is more experienced than Lucky and Naga :?

At least in being a Kyuranger, she's been one longer. Though Naga was active plenty before, and Lucky was up to something.

Lucky got his "luck" and possess the amazing typical red plot armor for 90% of the time. Naga got some special ability. Hammy is always getting sidelined as just a filler female member. Spada is also one of original core three and the rational one, but the writers always write him as a worry wart even though he have his point.

Raptor
Stinger
Lucky
Champ
Shou Ronpou

Shishi Red
Ookami Blue
Kajiki Yellow
Chameleon Green
Washi Pink

If I could have a 6th, I'd say Tenbin Gold.

Based purely on who I think would work well together and get the job done:

Garu
Naga
Stinger
Lucky
Spada

Based on just picking my favorites who I'd want to see in an episode together:

Hammy
Spada
Champ
Balance
Xiao