Potato Mine: Kills zombies early on, but hard to use as the level advances.
Cabbage-pult: More or less Peashooter. Get the card so it doesn't bother you later on. In Temple of Bloom, it's given to you so as to attack Excavator Zombies. Use it for that until you have better plants.
Bloomerang: Especially since Laser Bean and even more since A.K.E.E., it's weak and its AoE is pathetic. It's kind of acceptable in early levels, though.
Iceberg Lettuce: Locking one zombie at a time? Hurrikale and Stunion are better here besides the Plant Food, and Stallia is almost 100% better. Get its card for the Plant Food effect and nothing else.
Grave Buster: For Pyramid of Doom and Arthur's Challenge. Crucial in both.
Bonk Choy: Chickens? Prospectors? Sucks against Gargantuars and their Imps.
Repeater: Potential early shooter if I had enough seed slots.
Twin Sunflower: Best Ancient Egypt plant, bar none. Crucial for planting expensive plants like Winter Melons, which are crucial for getting far.
Snow Pea: Cheap, but Winter Melon slows groups. Get the card so it doesn't bother you later on.
Kernel-pult: Weak, butter prefers not to help. Get the card so it doesn't bother you later on.
Snapdragon: Okay area of effect plant, but counteracts Winter Melon and Iceberg Lettuce. Chickens?
Power Lily: Great for all Endless Zones. Best premium plant.
Spikeweed: Chickens if there are no Gargantuars. Otherwise, get its card so it does not bother you later on.
Spring Bean: In Dead Man's Booty, it's a good early attacker, and helps with Gargantuars. In all other Endless Zones, one zombie at a time goes one tile backwards? Either use the Blover and Plant Food combination or get the card so it doesn't bother you later on.
Coconut Cannon: Decent plant, but not worth it if not needed. Minecarts? Strawburst is better, really.
Threepeater: Three Peashooters so it sucks. Get the card so it does not bother you later on.
Spikerock: Chickens if there are Gargantuars, Gargantuar-thrown Imps if minecarts are not present, but not worth it if unnecessary. Get the card so it does not bother you later on in Tiki Torch-er.
Cherry Bomb: Best Pirate Seas plant. Effective against everything but Imp Dragon Zombies.
Squash: Can kill Gargantuars cheaply and effectively, although it prioritizes location over density.
Split Pea: Prospectors in low amounts or get the card so it doesn't bother you later on.
Chili Bean: Against eating zombies that aren't machines and a potential quasi-Imitater Potato Mine, but not worth it if unneeded.
Torchwood: Perhaps, unless you want to use its Plant Food effect, especially in Icebound Battleground, get its card so it does not bother you later on.
Pea Pod: Minecarts, but not much better than individual Peashooters or Winter Melon. I kind of like it, though. Eh, get the card so it does not bother you later on.
Lightning Reed: For Chickens and Chickens only. Elsewise, get the card so it does not bother you later on.
Jalapeno: Okay, but zombies tend to spread out in multiple rows. Cherry Bomb and Hurrikale work much better.
Melon-pult: Saves sun when you would otherwise plant more Winter Melons, but not worth the seed slot if unneeded.
Tall-nut: Good bulk and saves butt(e)s from Bulls, but in many cases, Infi-nut is better.
Winter Melon: Best Wild West plant. Effective against most all zombie types (damn Chic*nts/Welectronic artssels/Jesturds).
Imitater: Either a time saver or a waste of a valuable seed slot.
Laser Bean: Weak, but good crowd control. Anti-Imp Cannon and Prospector.
Blover: When given, it is great. Too bad not all Endless Zones give it, even though they give plants which are useless. In Dead Man's Booty, get it as soon as you see it, even if another plant shows up.
Thyme Warp: Great for Greatest Hits to save lives and time. That said, be warned that it removes effects and damage.
Electric Blueberry: Random and unreliable targeting system. Get the card so it does not bother you later on.
Garlic: Fragile and zombies are prone to avoiding this. Experimentation only.
Spore-shroom: Cabbage-pult with a useless extra ability. Get the card so it does not bother you later on.
Intensive Carrot: Powerful, but usage may be hampered due to a lack of seed slots.
Jack O' Lantern: Good ally, especially in Icebound Battleground, but beware unfrosting and Imp Dragon Zombies... and be alert.
Grapeshot: Same as Cherry Bomb, but has a flying chance against Imp Dragon Zombies... but then Jester Zombies ruin the fun, and there might be a problem with pacing when Chickens or Weasels are involved.