Blob download and image display in edit form (important for Editor with hidden fields in select and SQL command)
Add title to Logout, edit (in select) and select (in menu) for style "hever"
Export by GET parameters
Draggable columns in alter table (thanks to Michal Manak)
<option class> for system databases and schemas - information_schema and driver-specific (thanks to Vaclav Novotny)
Define foreign keys name - http://forum.zdrojak.root.cz/index.php?topic=185.msg1255#msg1255
Skinnable plus.gif and other images - http://typo3.org/extensions/repository/view/t3adminer/current/
? Filter by value in row under <thead> in select
? Column and table names auto-completition in SQL textarea - http://blog.quplo.com/2010/06/css-code-completion-in-your-browser/
? Aliasing of built-in functions can save 7 KB, function minification can save 7 KB, substitution of repetitive $a["a"] can save 4 KB, substitution of $_GET and friends can save 2 KB, aliasing of $connection->query can save 24 B, JS Closure compiler can save 2 KB, not enclosing HTML attribute values can save 1.2 KB, replacing \\n by \n can save .3 KB
? Branch binary_compile: LZW compression of all texts can save 11 KB, using chars 127-255 in minification can save 1 KB
Editor:
Three-state checkbox for boolean searches
JavaScript data validation - columns containing word email, url, ...