Anyone has good Spectres?

ive been using the Frost Wraiths from Act 1, is there any other good spectres or potentially op ones?

There are yes. I don't have a good knowledge of them, but there are certainly some powerful ones. You would probably want to look up a spectre build guide to know which ones are best and which are best for using while levelling. Some of them are only available later on from certain areas, like league mechanics, harvest influenced etc. Probably Ghazzy build information has some information about this, since he plays a lot of minion builds. POB also has some information about spectres, you can add certain ones to your build, though I don't know if it shows you the exact stats they give. Frostbears is apparently pretty good currently, it is findable sometimes in verusium ore, but you wont find that during the campaign I don't think.

There are also the corpse items which have been added recently. Some of them are quite good. It may be possible to get them off ritual in the campaign, but they are one use only.

https://www.poewiki.net/wiki/Corpse_item

I think in the campaign apes and slavedriver are some good ones, though charges from the apes got nerfed a while back. Not sure which is optimal for levelling, could be that it is not that important until you start mapping.