Once a day / Daily
These are the two accepted ways of saying something happens every day. It’s also possible to say “one time a day” but this can sound strange. When we use “daily” in a sentence, we often say “on a daily basis” (we can replace “daily” with any other time such as weekly, monthly, etc.)
Once a week / Weekly
Just like the first one, but for weeks.
Twice a week / Twice weekly
We can say “twice” instead of “two times”
Three times a week
But we don’t say “thrice” (unless you want to sound very old-fashioned)
Every other day
This is very useful – it means happening once every two days. So in a week, it would happen on Monday, Wednesday, Friday, Sunday, etc.
Every 2 weeks
We can say “every” + “time” to say it happens once in that time and repeats. For example: I have my birthday once every 12 months.
Every now and then
This means the same as “sometimes” or “occasionally”
Biweekly? Biannually?
I would recommend not using these. There’s a lot of confusion because it can mean two things. It can sometimes mean “twice a week” or “every 2 weeks”. So to avoid confusing people, use a different phrase.