I'll do 26 monsters, one for each letter of the alphabet. Let's get started.
Azer => Lazer (Laser-shooting elemental dwarf)
Blights => Lights (Just floating lights that move away as you get closer.)
Crawling Claw => Crawling Law (An animated congressional bill.)
Deva => Diva (Who doesn't want to fight pop-stars?)
Elemental => Alemental (Basically a water elemental but made of ale.)
Flameskull => Blameskull (An annoying skull that blames others for crimes.)
Grung => Grunge (Heavy metal-loving poisonous frogs.)
Hell Hound => Bell Hound (A dog covered in bells. It will never be able to sneak up on you.)
Invisible Stalker => Invisible Talker (An invisible air elemental that talks a lot.)
Jermlaine => Germlaine (Tiny, disease-carrying humanoids that live in the Underdark.)
Keg Robot => Beg Robot (A robot that won't stop asking for your spare change.)
Lich => Lick (A giant, floating, undead tongue.)
Merrow => Marrow (An awakened pile of bone marrow.)
Nothic => Gothic (Need I say more?)
Oozes => Boozes (Animated alcoholic beverages.)
Pseudodragon => Pseudo-Dagon (Someone pretending to be Dagon.)
Quetzalcoatlus => Pretzelcoatlus* (A snake made of a pretzel.)
Roc => Rock
Shambling Mound => Shambling Hound (A clumsy dog.)
Treant => Tree-Ant (An ant . . . that lives in trees.)
Umber Hulk => Lumber Hulk (The umber hulk's tree-chopping cousin.)
Velociraptor => Velocity-Raptor* (A physicist dinosaur.)
Wight => Wright (An undead contractor.)
Xvart => Xfart
Yugoloth => Bug-o-loth (Insect demon?)
Zaratan => Sara-tan (A tan woman named Sara.)
* (I know these technically break the rules, but I don't really care.)