"Evolution
As detailed in Memorandum: Indrik Emergence & Formal Development, Indrik can evolve when fed enchanted berries. There are four possible evolutions of the base indrik. Their evolutions correspond with the original feathers used to summon the base mount. Berries can be obtained in various events throughout 2019."
If I good understand, now wait on new event in 2019. But what can I do now with collected tickets ??
You could buy more feathers.
Once you mutate your Nascient Indrick to Dawnwood Indrik, your Nascient Indrick becomes unlocked leaving you free to re counjure it and have both Indricks at the same time.
You can buy more feathers, for the purpose of starting another nascent indrik, but be aware that you can't start that second indrik even with a second full set of 4 feathers, until you have evolved the first indrik with 4 berries. This may help you decide whether or not to get the additional feathers.
Also, there may or may not be other things to do with tickets other than indrik-related, but ZOS has made no such commitment or indication thus far. The thing is that it might take the better part of a half year's worth of events or more to get enough tickets for the feathers and berries for each morphed indrik, so it's possible that they may not do anything else with the tickets for another 2-3 years or more, waiting for everybody to get the 4 evolved indriks plus a 5th nascent....hmmmm....