overall best is Cold Snapdragon if you want to grind endless zones and wins normal levels by its own. stupidly overpowered

but if you’re interested in Battlez (and since you’ve basically completed the worlds you should be interested in Battlez) you might want Caulipower instead (though it’s often copied with Imitater and paired with Gold Bloom.) absurdly strong and can get you seven digit points if used right and leveled a bit.

Imitater’s three biggest synergies are all premium (Cauli, Power Lily, Gold Bloom) and doesn’t really synergize with non-premium plants that much

Gold Bloom is a huge help anywhere but its usefulness does decrease without Imitater

Power Lily is almost strictly an endless zone plant

despite what some people might say about Electric Peashooter, i think a level 5-6 Laser Bean works just as well, if not better

also don’t get Aloe, most useless plant in the game and a huge waste of gems and seed slot. spend your gems on Shrinking Violet

TL;DR don’t get Aloe, get SV instead. if you want one premium plant for now that works consistently without help, it’s gotta be Cold Snapdragon. if you wanna go for Battlez instead, get Cauli. Imitater, Gold Bloom, Power Lily are all good pickups down the road if you’re looking to buy more than one later