Everything from T1 frigates up. New pilot friendly ships are almost always an option, either as part of a fleet, or as a supplemental fleet that takes part in a larger operation. Doctrines change with the meta and with our strategic goals, but right now our most used doctrines are FYF frigates (newbee-friendly EWAR frigates that are handed out as part of the free ship program), claws, jackdaws, hurricanes, and typhoons.
In the past, we’ve fielded megathrons, maelstroms, machariels, dominixes, and T3 cruisers, it all depends on what is the most effective given the meta and our goals. Sometimes those goals are winning at all costs, sometimes the goal is being able to sustain more losses than the enemy, and sometimes our goal is just to have fun.