While it is an RMSS book, the Essence Companion has a list called Arachnemancy. On that list is the Web spell, though at 3 different levels each one affecting more targets as the spell level increases.
As for the Entangle spells, you could base them off the Staying spells from the Essence Hands list (from RMFRP/SS) only have it be able to handle more weight, or just a certain number of targets like the Web spell above, as Staying is mostly a useless spell until you get to the really high level versions. (Actually, it is mostly useless until you get to the highest level versions, Staying True, when you can hold 10 lbs./level and actually affect things other than tiny objects and light furniture - or halflings.)