Whitebeard: HP: 3900. ATK: 1360. RCV: 235 Rank: 10/10 Special: Reduce enemy HP by 30%. Whitebeard could definitely be captaining his own team, but with his special and godly stats he can easily fit in nicely on a Striker team.
Blamenco: HP: 2488. ATK: 1252. RCV: 268 Rank: 7.5/10 Special: QCK and DEX into STR. Blamenco has very decent stats and his special is better suited for a STR team; however, paired up with the Kraken it's very easy to make a STR Striker team.
Eustass Kid: HP: 3515. ATK: 1298. RCV:69 Rank: 9/10 Special: Own orb into STR and 7X damage to all enemies. His stats are crazy high (besides his RCV) and his special is fun to continuously spam. Overall, he's powerful.
Kraken: HP: 2700 ATK: 1111. RCV: 33. Rank 7.5/10 Special: All orbs into either STR or QCK and random damage to all enemies. Kraken, paired up with Blamenco, can make a full team of STR orbs, and their both Strikers. Kraken also has decent stats
Alvida: HP: 1668. ATK: 999. RCV: 369 Rank: 10/10 Special: 80% damage reduction. Alvida gives you a massive defense boost which can easily save your life. She can be essential for many different battles.
Pearl: HP: 1904. ATK: 656 RCV: 129 Rank: 4/10 Special: Meat into STR. Pearl has quite a bit of health for being an otherwise weak unit. His special will only help a Striker team with almost exclusively STR units.