Stable Android 11 Download is available after its release since 8th September 2020. Since then we have seen many Android 11 based ROMs such as LineageOS 18, Pixel Experience 11, RevengeOS 4.0, StatiXOS 4.0 etc. for various devices.
Custom ROMs usually do not have GApps or Google proprietary apps built-in. So, developers provide Google Apps separately in recovery flashable zip format.
This page provides Android 11 OpenGApps download packages, both OFFICIAL and UNOFFICIAL.
Release date: 12th September 2020