There are 100's of Items that yamato can make from the Macross Franchise (Despite what ever License they hold or can obtain) especially the whole Zentradi / Meltrandi fleet of Mecha & Ships. Theres still many Valkyries that have never seen the light of day other than a few Resin Garage kits or scratch builds.
But then again its up to YAMATO to decide whether or not they can afford making new molds for toys that may appeal to some, but not enough to bring in major profits.
But Enemy Mecha, VF-4's, VF-2SS. VF-5000's, etc. would be big sellers and from most people on MW input a 1/3000 TV & DYRL SDF-1 would be big winners.
So in a nut shell, technically it would take many many years for YAMATO to run out of ideas, but if they just keep making the VF-1 with Canon & non-canon paint schemes, that may chase off many potential buyers to buy again.