I'm also a YNAB user (pre-subscription based). I try to keep my money wherever it will earn the most interest, but still available when I need it (checking is 2%, CDs are about the same, money market account with Credit Union). I just use my available balance to know what I have set aside for each category.
Things I budget for that are not monthly expenses:
Property taxes
Car Insurance
Natural gas (more in winter, pay ahead during the summer so I don't have constant small monthly bills)
Amazon Prime and Costco subscriptions
Household goods
Home maintenance
Photography club membership (even though it's only $25/year)
Post office box
Computer maintenance (mostly for my Kaspersky subscription)
Clothing
Car maintenance/repairs (includes oil changes, registration, tires, etc)
Health expenses (I have an FSA, but this helps fund things in case I go over reimbursement or don't get reimbursed)
Gifts
Christmas (this includes gifts as well as extra expenses, big dinner costs, whatever)
"Bulk Meat Purchases" (1/4 to 1/2 cow every year, buy chicken all at once, pork, bacon, whatever)
Taxes (tax preparation expenses)
Car replacement (hopefully not needed for a very long time)
Emergency fund (currently funded)
Vacation
New house build
College (for son, add to monthly, spend each semester)
Charitable
"eating out" (we don't go out to eat very often)
Garbage (billed every other month)
"Fun money" (although I budget/spend from this monthly, it can vary widely and covers my fun stuff, concert tickets, books, hobbies, etc)
"Quilting" (because this needs its own category!)