Mesh check is the perfect addon to help you clean your meshes.
Ngons
Triangles
N-poles
E-poles
Poles with more than 5 edges
Isolated verts
Non-manifold edges
Mesh check will flush them out for you.
It works on 1 or a selection of objects, both in object mode and edit mode.
The display color is customizable from the addon preferences.
The addon allows you to see the different elements through the mesh by activating the X-Ray option.
Mesh check is also very handy before exporting an asset for 3d printing to check if it is closed for example.
You’ll find the addon in the Overlay menu of the 3D view.