Legacy deck built around a lot of combos using Aluren and Cloudstone Curio

I built this deck probably 8 years ago and took a long break from MTG. I am trying to search through cards that have been released since I stopped playing that would fit well into this deck.

I have put a bunch of possibilities in my maybeboard and should probably just playtest a bunch of options.

Also, I never really used to play with sideboards and I would like to create a good one for competitions.

Does it make sense to put Brainstorm in? What would i replace?

Counterspell or other control things to slow opponent until I can get my combos out?