Does anyone know what (if any) ingredients I can use to make the potion of strength in Skyrim?
There's a few ingredients that have the "Fortify Carry Weight" attribute:
Bryan points out that the following combos have additional effects:
I'd avoid the two combinations which yield poison effects, unless you have the relevant alchemy skills to negate them.
Creep Clusters are pretty easy to find, and Giant's Toes are easy to find but not so easy to separate from the rest of the giant. Scaly Pholiota are found growing on trees and stumps and the like. Those are probably the easiest to find in normal situations.
Hawk Beaks generally require that you kill hawks, which is not that easy to do. We covered killing them in this question although Bryan also points out that lightning spells work well as well. Wisp Wrappings are relatively rare in shops (killing Wisps yields them the most often), and River Betties are a type of fish in streams and lakes, which may be a bit tricky to find in large quantities.