What is the symbol on the left side of the page (the fist with the cross, arrow, and arrow-cross) called? What is its history?
It's the #trans symbol with the liberation fist in the air symbolizing the intersectional approach needed to respond to systemic oppression. The trans symbol grew out of the trans community conceptualizing the intersections of cultural gender symbols.
Consider the way the trans community conceptualized these symbols in 1975:
http://i2.wp.com/research.cristanwilliams.com/wp-content/uploads/2012/08/005s.jpg?resize=373%2C560
... and in 1976:
http://i2.wp.com/research.cristanwilliams.com/wp-content/uploads/2012/01/tran-evolution.png?resize=412%2C616
The current incarnation of these symbolic conceptualizations are attributed to Holly Boswell in 1993.
Consider the way the trans community conceptualized these symbols in 1975:
http://i2.wp.com/research.cristanwilliams.com/wp-content/uploads/2012/08/005s.jpg?resize=373%2C560
... and in 1976:
http://i2.wp.com/research.cristanwilliams.com/wp-content/uploads/2012/01/tran-evolution.png?resize=412%2C616
The current incarnation of these symbolic conceptualizations are attributed to Holly Boswell in 1993.