[With an unashamed bias towards the transforming ones based on original toys, regardless of how important they are in the Anime. I've mentioned their Western names for clarity, though it should be stressed that they aren't the same characters, just based on the same figures.]
BLUE JET [Fitor]
A swordsman of the Jet Tribe, and one of the leads of the series. Rarely seen without the sword, which he usually uses to kill a huge number of Gylandar in a highly stylised fashion. A bit serious, but basically alright.
ROD DRILL[Screw Head]
Another lead, and another swordsman, this time from the Battle Tribe. Rod Drill's probably my favourite character from the Anime, being funny without being particularly irritating. Love the animation model, too.
Japanese-exclusive toy. Reina's personal transport and helper, and as his name suggests, a triple-changer. Nominally a member of the Battle Tribe, but he does even less fighting than Reina...
Based on a Japanese-exclusive playset-type figure originally released in 1983, Command Buggy's dad runs a mine that's targetted by Casmodon. Buggy is a childhood friend of Rod Drill, and after his father is killed leads the Battle Tribe working at the mine to help Rom and the others drive off the Gylandar.
A Tank Transer (a Japanese & European release), Trim gets a decent-sized guest role in one episode. A childhood friend of Drill's, his lover was killed (and Trim was ultimately fatally poisoned) by Baltonic bombs, and he then steals the local king's Baltonium supplies so the same can't happen again. he dies, but Rom and company avenge him by dethroning the corrupt king.
Modelled on the DrillHeli Double Machine Robo figure, Vilion is the head of Triple Jim's home village, which is under attack from the outlaw Bug Newman. Vilion does his bit helping driving off Newman and his Gylandar allies.
LIMOSUINE ROBO [Tux]
This is one of my favourite cameos, with the distinctive Limosuine Robo redone as a hearse in the city of Under Cronos, defending the alleged convict Brocco. Interestingly, the prototype of this figure was in these colours...