libes is a library for managing an entity system written in C++11. It is based on the core concepts developed in the Entity Systems Wiki: entities (a unique id for game objects), components (the data for an aspect of a game object), systems (the code for some aspects of a collection of game objects).
libtmx is a C++11 library for reading TMX files. TMX (Tile Map XML) is a XML dialect used in Tiled, a tile map editor. libtmx is not meant to modify TMX files but to read TMX files. Its main use case is for games that use TMX maps. The library is not a rendering library, so it does not depend on any graphical toolkit.
libsuit is the SFML User Interface Toolkit (SUIT). It is a simple and hackable library for defining actions and widgets. It also provides some predefined widgets like a video configuration widget. If you want a more complete alternative, you can try SFGUI for example.