Here's those characters from Bowser Kingdom - Hal the Koopa, Jeff the Goomba and Steve the Piranha Plant.
They have returned in SMBGT - Special Saga: Dry Bowser Arc.
Bowser give them one last, I mean final, change to succeed their plans to destroy Mario Bros. If not... then they are banished from both Mushroom Kingdom and Bowser's Kingdom.
Super Mario Bros GT The Grand Adventure aka SMBGT TGA (c) Yours Truly
Characters (c) Nintendo
Hal, Jeff and Steve (c) araskin500 and pthouse