TOP: Garen and Malphite their kit skills are simple.
JG: Master Yi easy to use since it requires little attention to deal a lot of damage to the opponents, just by having good items. Amumu has a lot of stamina and is good in team fights
MID: Lux and Annie, lux can be a bit difficult when it comes to getting skills right but with practice you can.
ADC: Ashe and Tristana, Ashe is one of the easiest adcarries to learn if what we are looking for is to master this position and learn to farm and Tristana is easy to use due to its ability to farm waves in a simple way, it generates a lot of damage constantly and with abilities to escape from complicated situations.
Support: Leona and Nautilus, Leona has a very good initiation and has a lot of stamina. The only drawback she has is that if she commands, there is no turning back and Nautilus, more of the same, has a good way of escaping if necessary.