Here is my list of A+ Primaris units for Space Marines in no particular order:
Hellblasters with standard Incinerators:
S8 AP4 2 (super charged) dmg rapid fire 30” range
They make things go away fast. Probably the best unit for the points.
Plasma Inceptors:
Can deep strike and d3 shot per gun. Plasma is the go to weapon for SM. I run a squad of five and they are absolutely amazing.
Intercessors:
I run five man squads with a grenade launcher and power sword - 95 points. They let you sink points into more uber units and get work done.
Redemptor:
Super ranged weapons platform. You can run a tandem.