DBIx::AnyDBD is a Perl module for developers writing cross database applications. It allows you to write "plugins" for different DBD drivers (Oracle, Sybase, etc) so that your application can do different things on different databases. It doesn't provide any compatibility layer - just an intelligent method to switch to the right class to use at runtime.
DBIx::Password provides an abstraction layer for password maintenance. It is database independent and only overrides the connect method (so it basically behaves as DBI normally does). You provide a single virtual user name in the connect method and the module determines which database/which user/which password to provide.
DBMEdit is a web-based DBM database editor (in Perl 5). If you use DBM files and don't have a simple way to edit them, you'll want this. It treats each element in the DBM as several fields joined by a delimiter, in effect supporting multiple columns within the single-column DBM format. DBMEdit displays your DBM database as a table, and provides auto-sized forms to add or edit records. Multi- user access is safe.
DB_Browser is a CGI tool for developers working with any relational database supported by Perl::DBI. It easily facilitates searching, editing, and adding to tables within a database. While it can be used as a regular interface to database data itself, it works well as a supplemental tool for developers creating their own primary interface.