tool to visualize a collection of phylogenetic trees
I recommend using densitree: https://www.cs.auckland.ac.nz/~remco/DensiTree/

And rwty: https://github.com/danlwarren/RWTY

Densitree plots the superimposed set of trees in a heatmap-like format: 

And rwty, a very powerful R package that allows visualisation of treespace in an NMDS format (among other methods):