I parsed the DBD search results, grabbed modules with DBD:: and sorted by the 'direct dependents'. I'll start with the ones with more dependents. There were 94 modules that contained DBD::. Here is a list in case someone else needs it:
950 DBD::DBM
511 DBD::SQLite
94 DBD::mysql
75 DBD::Pg
26 DBD::Mock
23 DBD::CSV
10 DBD::ODBC
5 DBD::Oracle
4 DBD::Sybase
4 DBD::XBase
3 DBD::AnyData
3 DBD::MariaDB
3 DBD::SQLite2
2 DBD::Excel
2 DBD::Informix
2 DBD::Sys
1 DBD::ADO
1 DBD::DB2
1 DBD::Ingres
1 DBD::PO
1 DBD::PassThrough
1 DBD::RAM
1 DBD::XMLSimple
0 AnyEvent::DBD::Pg
0 Bundle::DBD::PO
0 Class::DBI::ClassGenerator::DBD::mysql
0 DBD::Adabas
0 DBD::Amazon
0 DBD::AnyData2
0 DBD::Avatica
0 DBD::BlackHole
0 DBD::Cassandra
0 DBD::Cego
0 DBD::Chart
0 DBD::Crate
0 DBD::DBMaker
0 DBD::DtfSQLmac
0 DBD::Firebird
0 DBD::Fulcrum
0 DBD::Gofer::Transport::http
0 DBD::Google
0 DBD::IngresII
0 DBD::InterBase
0 DBD::JDBC
0 DBD::LDAP
0 DBD::Log
0 DBD::MVS_FTPSQL
0 DBD::MaxDB
0 DBD::Mimer
0 DBD::Mock::Session::GenerateFixtures
0 DBD::Multi
0 DBD::Multiplex
0 DBD::Neo4p
0 DBD::Ovrimos
0 DBD::PgPP
0 DBD::PgPPSjis
0 DBD::PgSPI
0 DBD::Plibdata
0 DBD::PrimeBase
0 DBD::RDFStore
0 DBD::SQLAnywhere
0 DBD::SQLcipher
0 DBD::SQLeet
0 DBD::SQLite::Amalgamation
0 DBD::SQLite::BundledExtensions
0 DBD::SQLite::FTS3Transitional
0 DBD::Safe
0 DBD::Salesforce
0 DBD::SearchServer
0 DBD::Simulated
0 DBD::Solid
0 DBD::Sprite
0 DBD::Sqlflex
0 DBD::TSM
0 DBD::Template
0 DBD::Teradata
0 DBD::TimesTen
0 DBD::TreeData
0 DBD::Unify
0 DBD::WMI
0 DBD::WTSprite
0 DBD::Wire10
0 DBD::Yaswi
0 DBD::drizzle
0 DBD::iPod
0 DBD::mSQL
0 DBD::monetdb
0 DBD::mysql::AutoTypes
0 DBD::mysql::SimpleMySQL
0 DBD::mysqlPP
0 DBD::mysqlPPrawSjis
0 DBD::mysqlx
0 DBD::pNET
0 Module::Build::DBD::Pg
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