Plenty of glass and ceramic containers are available, but they almost all have plastic lids, which isn't great if food is reheating and the water's condensing on the plastic and dripping back into the food.
What's the status of silicone? Silicone container covers are available, which won't seal but will work to prevent spatter.
Since I don't have any of those yet, and all my glass or ceramic containers have plastic lids, I've been avoiding my microwave. Instead, I've steam-reheated ceramic and glass food containers, uncovered, in a pressure cooker. It's not as quick, but there's little to no plastic exposure (except the silicone sealing ring, if that leaches microplastics into the steam, but it's still probably vastly less than reheating with a plastic lid on) and it heats more evenly too.
What's the status of silicone? Silicone container covers are available, which won't seal but will work to prevent spatter.
Since I don't have any of those yet, and all my glass or ceramic containers have plastic lids, I've been avoiding my microwave. Instead, I've steam-reheated ceramic and glass food containers, uncovered, in a pressure cooker. It's not as quick, but there's little to no plastic exposure (except the silicone sealing ring, if that leaches microplastics into the steam, but it's still probably vastly less than reheating with a plastic lid on) and it heats more evenly too.