I think we will see Ghost Rider, Blade and Punisher in the near(ish) future.
Among the characters that haven't gotten to play in the MCU sandbox, considering what we already know about the upcoming Phase 4 and Netflix slate, I'd say that those three are (arguably) the most high profile Marvel characters left.
Here's how I see it going down...
I think Luke Cage, Iron Fist and Jessica Jones were picked as Netflix shows for a very specific reason... those three characters have very strong ties to each others' worlds. I think those three shows, going forward, will be merged and continue as Heroes For Hire. This leaves a couple of slots. I think those can be filled with Moon Knight and Punisher.
On Netflix...
Wave 1: Daredevil, AKA Jessica Jones, Iron Fist, Luke Cage, The Defenders
Wave 2: Daredevil (season 2), Heroes For Hire, Moon Knight, Punisher, The Defenders II
Now on the movie side, I think a solo Ghost Rider or Blade movie is a bit of a risk considering the fact that, as of now, Marvel expects their solo movies to absolutely explode in the box-office. While I have no doubt either Ghost Rider or Blade would make a solid profit, I don't think we'd be seeing returns at the level of GOTG/CA:TWS. So, my idea would be to combine the two. Ghost Rider/Blade team-up movie! One or two other supernatural hero characters could also have cameo appearances.
Supernatural-oriented movies in Phase 4...
2019: Dr. Strange 2
2020: Blade/Ghost Rider team-up movie
2021: Midnight Sons (Dr. Strange, Blade, Ghost Rider, Moon Knight brought over from Netflix, etc.)
...2022 would bring Avengers 4 (The Coming of Galactus, if we're lucky) as usual, but that's a topic for another discussion.
EDIT: As an addendum, if they think Phase 4 is looking a little too supernatural heavy, maybe they could shift Midnight Sons to 2023 to kick off Phase 5 with a bang just like CA:CW is currently set to kick off Phase 3.