If you want zero risk you will not get much or any return. Your only options are high yield savings, CDs, and extremely short term treasuries/bonds (e.g., EE or I bonds).
Small correction, EE and I bonds are long term bonds (20 years to get the value doubling on EE bonds, which is the only reason to own them, but the implied ~3.5% of that makes them very competitive with other long term options atm). But the general point of your comment is right, 3.5% risk free isn't bad at all compared to most options.
Good point, I-bonds can be redeemed after 12 months, but they have a 3 month interest penalty if you redeem them before 5 years. But that's really not bad at all. So they're long term in that they guarantee their base rate for a long time, but are unusually liquid in that they can be redeemed very flexibly.
I really like those two bonds. I guess that's why they're limited to $10k/yr each :-)
