Zords (Power Rangers franchise and two Super Sentai series)
Various named Sentai mecha (Super Sentai franchise)
When Dib's (Invader Zim) skeleton was crushed by a paramedic in a freak piggy accident in an alternate timeline, his father Professor Membrane created for him the MegaBoy 3000, a fusion-powered titanium exoskeleton that "gave give him the strength of ten thousand little boys!"
The Black Knight (Sly Cooper: Thieves in Time) is a mechanical mecha Penelope created who's using a rocket launcher...
.. and later upgraded with a laser and a shield.
Jak's Titan Suit (Jak II)
The Nega Egg Wisp (Sonic the Hedgehog) is one of Eggman's final battle mechas.
Koala (Rave Master) with His DarkBring Machinery can create robots and pilot them as well.
EVA-pilots (Neon Genesis Evangelion)
Battle Jacket (Dragon Ball)
Emperor Pilaf and his minions (Dragon Ball) in their "Pilaf Machines".
The Power Rangers (Power Rangers) are well known for their various Megazords such as the Dinozord. Additionally the Super Sentai franchise that Power Rangers was based off of have a long standing tradition of using various mecha as part of each of their series.
Being a mechanical engineering genius, Tron Bonne (Megaman Legends) is able to create small robots called Servbots and pilot large aerial battles ships and mechs.
Despite being a small, petite girl, Heloise (Jimmy Two-Shoes) is very intelligent and sadistic as she makes inventions for Misery Inc. that would spread misery to her town and also likes to destroy things for fun.
Gurren Lagann (Tenna Toppa Gurren Lagann)
Dandy (Space Dandy) makes up for his lack of proper combat skills by utilizing his mech, Little Aloha.
E-99 Eggsterminator (Sonic X) is a powerful robot mech created by Dr. Eggman. Being powered by six of the seven Chaos Emeralds, it was enough to surpass Sonic in both strength and speed.
DJ Octavio (Splatoon) pilots the Octobot King.
D.Va (Overwatch) is a master mech pilot despite being only 18 years old.
The Ecto-Skeleton (Danny Phantom) was capable of amplifying Danny's ghost powers 100 fold, but at the cost of drastically exhausting his body.
Franky's (One Piece) greatest weapon is gigantic military robot created using state of the art technology designed by Vegapunk.
The Vox Pilots, Muginami, Madoka Kyouno and Lan with their respective Vox Units (Lagrange: The Flower of Rin-ne).