Seil is described as 'PCKeyboardHack can change caps lock key behavior. For example, changing caps lock key to delete Key' and is an app in the System & Hardware category. There are more than 10 alternatives to Seil for Windows, Mac, Linux, BSD and X11. The best alternative is SharpKeys, which is both free and Open Source. Other great apps like Seil are Karabiner Elements (Free, Open Source), KeyTweak (Free), Key Manager (Paid) and Key Remapper (Paid).
SharpKeys is a utility that manages a Registry key that allows Windows to remap one key to any other key. Included in the application is a list of common keyboard keys and a Type Key feature to automatically recognize most keyboard keys. It was developed in C# using .NET v2.
Karabiner, previously called KeyRemap4MacBook, is a very powerful keyboard remapper for Mac OS X. In addition to simple key remapping, it has special remapping modes like Emacs-mode, SandS-mode (Space and Shift).
The xmodmap program is used to edit and display the keyboard modifier map and keymap table that are used by client applications to convert event keycodes into keysyms. It is a part of the X.Org project.
Do you want to remap keyboard keys with another key ? Do you want to remap mouse buttons ? Then try Key Remapper. With Key Remapper you can easily remap key or remap mouse buttons with another key, program, mouse button, custom text.