Hey Sjiggie, welcome aboard!
As Andorax said, focusing on one type of summons might not be the best solution - flexibility and diversity are as important as a strong type of summon.
But rest at ease… clerics can cast summon undead, summon monster and conjure ice beasts. So as long as you keep all of this in mind, a cleric will do just fine.
The summon domain is an obvious choice for the domain spells and the +2 caster level.
I’ve got some ideas for casters floating around in my head currently - if you want, I can aid you in creating a summoner of your choice, be that a cleric or another.
And I can help you in greater detail than Andorax can, him being DM and all that. Go ahead and PM me if you want to exchange some ideas.