There could be multiple questions regarding travel cards of various states in various countries. For example in Washington DC it's the SmarTrip card, in New York City it is the MetroCard in the USA. In Australia, for Australian Capital Territory (ACT) it's the MyWay card and in New South Wales (NSW) it's the Opal card.
Therefore to group the questions on these travel cards related questions can we create 'travel-card' tag?
If I have a question about a stored value card for use on mass transit, it really means I have a question about the transit system. A question about how a Presto works is a question about how TTC works, not about what analogies I can draw from an Octopus or a CharlieCard. As such, I'd expect questions about a Rabbit Card or a TAP or a Suica to be tagged as public-transport plus payment-cards plus the locale (e.g. los-angeles) until the system attracts so many questions that it merits a tag of its own (e.g. oyster-card, tfl).
At the least, I would advise against the term "travel card," which in my circles refers to travel-oriented credit cards like the Sapphire Reserve or the Bonvoy Brilliant cards, and which in my parents' circles refers either to "city passes" where admission to various tourist spots is sold as a bundle.
It's not a good idea because there are multiple different kinds of things that different people call "travel cards". And for the sense of "travel card" that you have in mind, there's a good chance that sense also goes by other terms in some places or by some people or services.
Years ago I'm sure we defined the "tickets" tag to specifically cover the kinds of travel cards which are basically various kinds of tickets/passes/etc.
Many specific kinds of tickets, passes, and cards already have their own tag. Use or create that tag and also use the generic ticket tag, that's if I've correctly assumed you're asking about the ticket sense of travelcard.
