But let's see what CAs everybody is authorizing via their 'issue' and 'issuewild' records.
In total, I found almost 2,200 distinct 'issue' records (for domains in all TLDs, 456 distinct for the Top 1M domains) and 878 'issuewild' records (all TLDs, 227 Top 1M).
Here are the top 20 CAs:
But... let's carefully read RFC8659 again.
The 'issue' tag grants
"authorization to issue certificates containing that FQDN to _the holder of the issuer-domain-name or a party acting under the explicit authority of the holder of the issuer-domain-name_."