Eldritch Invocation: Eldritch Blade Flurry (Patreon)

The idea for this is based on a request on Reddit.

I went with level 15 as a requirement, along with needing to have eldritch blast and Pact of the Blade.

It's basically a replacement for Thirsting Blade at higher levels, giving a 3rd attack. I didn't go with four attacks just so that fighters are the only class that gets 4/turn.