Where to find bands for 2nd generation Apple Watch?

Basically the same answer that I provided you for the 1st generation Apple Watch.

Apple Watch bands are surprisingly cross-compatible across generations, with Apple sticking to two main band width sizes: 38/40/41mm and 42/44/45/49mm. So, rather than every Apple Watch model having its own exclusive set of bands, they’re grouped by case size compatibility.

If the band says 38/40/41mm, it fits any watch in that small-size group. If it says 42/44/45/49mm, it fits any large-size watch, including the Ultra.

So, it will depend on the case size for the 1st generation Apple Watch.

For 38mm, they are the:

• Solo Loop
• Braided Solo Loop
• Sport Band
• Sport Loop
• Milanese Loop
• Leather Link
• Modern Buckle

For 42mm, they are the:

• Solo Loop
• Braided Solo Loop
• Sport Band
• Sport Loop
• Milanese Loop
• Leather Link
• Link Bracelet
• Ocean Band
• Alpine Loop
• Trail Loop

Regardless, you can get them directly from Apple or literally dozens of other sources.