With two F4 champions (Lirim Zendeli in ADAC F4 and yesterday Kiern Jewiss in British F4) crowned and a few more to come, here's some silly season guesses for the 2019 F4 championships.
ADAC F4
Leaving
Lirim Zendeli and Frederik Vesti depart for the new FIA F3 category.
Liam Lawson departs for either Pro Mazda (or whatever it will be called), British F3 (or whatever it will be called) or EF Open.
Enzo Fittipaldi and Olli Caldwell leave for one of the new regional F3 championships.
Mick Wishofer, Leon Kohler and Charles Weerts leave for EF Open.
Tom Beckhauser departs for new pastures.
Staying
Krutten, Ptacek (as part of a dual campaign), Petecof, Cohen, Cordeel (full-time) and Safar (full-time) return for a second season.
If he doesn't commit full-time to EF Open next year, David Schumacher returns for another shot at the title.
Joining
David Vidales and Roman Stanek (if added to the FDA) join for a dual campaign with Prema.
Some karters from this year's DKM championship.
Some other random names.
British F4
Leaving
Simmons, Ericsson, Hoggard and Pasma leave for British F3.
Champion Kiern Jewiss departs for either British F3 or (if he is added to the Ferrari Driver Academy) one of the regional F3 championships.
Hauger and Doohan leave for Arden's FR2.0 (or whatever F3 name they give it) division.
Tonteri moves to either British F3 or EF Open.
Sharp departs for newer pastures.
Remaining
Lucca Allen, Seb Priaulx, Sebastian Alvarez and Josh Skelton stay for a second season.
Joining
Red Bull juniors Harry Thompson and Jonny Edgar join the championship, likely with Arden.
Karters Dexter Patterson, Zane Maloney and Callum Bradshaw come aboard.
Some names from Ginetta Juniors (likely Adam Smalley, Louis Foster and Luke Browning).
Some other random names.
Other
Carlin rejoin the championship (who they'll field, I don't know).
French F4
Leaving
Collet, Pourchaire, Leclerc, Eteki, de Pauw and de Wilde leave for the regional F3 championships.
Staying
The Muth Brothers stay on for a second season.
Various other names do to.
Joining
French karters Victor Bernier and Hadrien David come aboard.
Some other French and Belgian karters too.
Italian F4
Leaving
Fittipaldi and Caldwell leave for the regional F3 championships.
Leonardo Lorandi and William Alatalo depart for the EF Open championship with RP and another team.
Other names depart too.
Staying
Ptacek, Krutten and Petecof stay on.
Other names do too.
Joining
Vidales and Stanek (if added to the FDA) join with Prema.
Karting champion Andrea Rosso joins the field.
Other names too.
Other
Charouz join the series.
Not sure about the other championships.