.da to see all databases - one called 'main'
tables of this database can be seen by
SELECT distinct tbl_name from sqlite_master order by 1;
The attached databases need prefixes you chose with AS in the statement ATTACH e.g. aa (, bb, cc...) so:
SELECT distinct tbl_name from aa.sqlite_master order by 1;
Note that here you get the views as well. To exclude these add where type = 'table' before ' order'