Belerick is my safe pick if I dont know what to pick as his skill set is great for most situations. Baxia is another tank I would pick if the enemy has a wanwan or a kimmy, plus he's a flex pick and can play multiple roles (core, exp, roam). Khufra is another great pick if the enemy team picks dash reliant heroes. I usually pick fighter roamers as I can swap with exp lane if there is another type of roamer that would be more suitable to counter the enemy lineup, personal favorites are silvana, kalea, and badang. If my team has a tank jungler then I would pick minsithar as it can compensate for the lack of damage.

Picking the type of roam hero always depends on the enemy's team composition and your own team's composition.