This is a list of the secret likes that I know of. If anyone can add to this I would like that very much.

Plant island
Pot Belly - Bloofi Tree
Toe Jammer - Hollow Log
Noggin - Fire Bush
Mammot - Stritch Skin
Wubbox - Tub Fountain
Shugabush - Bottomless Pitt
Ghazt - Unknown
Furcorn - Sumumpkin Patch
Fwog - Spurrit Statue
Drumpler - Sumumpkin Patch
Maw - Dragon Statue
Oaktopus - Spurrit Statue
Shrubb - Razzli Tree
Pummel - Bakery Oven
Clamble - Barbloo Statue
Bogart - Eerie Remains
T-Rox - Dragon Statue
Entbrat - Babayag Tower
Punkelton - Unknown

Cold Island
Tweedle - Harpsitree
Grumpyre - Bass String Bridge
Pango - Babayag Tower
Quibble - Castanevine
Dandidoo - Spurrit Statue
Spunge - Bloofi Tree
Thumpies - Dragon Statue
Congle - Meldablend
Dreedge - Squeed Statue
Yool - Unknown

Air Island
Reebro - Fazzle Tree
Cybop - Razzli Tree
Pom Pom - Toob
Scups - Dragon Tower
Riff - Crumbler Tree
Schmoochle - Yum Yum Tree

Water Island
Jeeode - Unknown
Reedling - Unknown
Shellbeat - Dragon Tower
Blabbit - Unknown

Earth Island
Humbug - Unknown
Quarrister - Zuffle Tree
Hoola - Unknown

Etheral Island
Nebulob - Unknown
Arackulele - Unknown
Whisp - Unknown
Boodoo - Unknown
Sox - Unknown
Kazilleon - Unknown

Shugabush Island
Shugabass - Unknown
Shugitar - Unknown
Shugajo - Unknown
Shugarock - Unknown
Shugabuzz - Unknown
Shugabeats - Unknown
Shugavox - Unknown