Each of those are very liquid and low risk, though ibonds have a 1-year minimum holding period and most CDs have penalties for early redemption (doesn’t apply to brokered CDs).
But the simplest option is to stick with a high yield savings account like Ally offers, or maybe a money market account (Ally offers one, many other banks do as well) or money market fund (pretty much any brokerage offers these). Those will keep your money very liquid, are dead simple, and you’ll probably get like 80% of the interest compared to other options.