Titling / Motion graphics software?

Well Adobe Stock mogrts and Motion Array are great resources where you can buy mogrts from,

In addition to all the wonderful help you got from fellow ACPs, I would like to add that

only the mogrts you create and export from Premiere Pro will go into Rush. So if you will 

also be using those mogrts in Rush, start the scratch from Premiere Pro and not After Effects,

although after effects gives you much more advanced motion graphics and animation controls.

You can check out Roland Kahlenberg's typeGEMS v2 . See this thread:

https://community.adobe.com/t5/premiere-pro/free-motion-graphics-template-typegems-v2-free-lite-version-with-40-text-presets/m-p/10349013?page=1

For what it's worth, a decent amount of graphics work can now be done right in Premiere Pro with the Essential Graphics panel. You can composite graphics into layers + groups and animate individual components of your graphics as you see fit. EG also supports templating meaning the work you do can be saved and re-used easily for other parts of your video or other projects. It even supports responsive design, meaning you can designate into/outro ranges for your animations that mean no matter how long you extend or shorten the graphic, your wipes ins/outs remain in-tact.

Some info here: https://helpx.adobe.com/premiere-pro/using/essential-graphics-panel.html and Adobe offers some tutorials on this, as well as you can probably just do a search for Premiere Pro Essential Graphics on YouTube and get tons of hits.

Of course if you want to take it one step further, the natural reccommendation would be After Effects which is built specifically for motion graphics and special effects. If you have full CC subscription, it may be worth checking out. AE can do a LOT, maybe even more than you need, but that doesn't mean it can't do more simple work too and is often better suited to do motion graphics. AE also can create templates for Premiere, and with a bit more flexibility, as you can control which properties can be visible and modified from within Premiere by your editor, and which cannot.

Of course, if you don't want to go down the road of crafting your own there are folks who sell their own motion graphics templates (MOGRTS) that you can install within Premiere (heck, Premiere even comes with some templates by default). I can't say I've ever bought one myself, so I can't make any site reccomendations.