The pollsters

[Sorenroy]

Both of these are tools that link to the PDFs for the polls they use. They also weight their polls using several different methods, one of which is accuracy. For 538 you just have to scroll down a little to get to the polls, but besides that they are a good place to start (besides going into the polls PDFs and looking through those for yourself).

http://projects.fivethirtyeight.com/election-2016/primary-forecast/iowa-republican/

http://elections.huffingtonpost.com/pollster

[Sorenroy]

Sorenroy provide the huffpollster link.  You can use them to remove internet pollsters and suspicious pollster that you don't like.  Huffpollster allow you to modify for trend.

It also allows you to select a single pollster and see their trend line and how far away from the average it is. That allows you to see how much of a swing they might have, or how far the over/under poll a specific person (some polls show Trump far lower/higher than others for example).