What major or well-known script-writing competitions exist for anime works? I'm familar with the Animeka anime script-writing competition, but it doesn't seem like there are many others out there. What major or well-known script-writing competitions exist for anime works?

Thanks
There seem to be three main anime script awards, at least in Japan. 

Tokyo Anime Award includes a wide variety of anime and categories, including two for screenplays. One is for screenplays and one is for original adaptation screenplays. These seem to be all professional/aired screenwriters/anime. These categories were created in 2014, though the Award is from 2002. 

Animax Taishō is for submitted rather than already aired anime, and the winners are produced and aired on Animax. It's not clear if this has been run after 2008. 

Kyoto Animation Awards is also for unpublished work, though oddly they seem to not have winners every year. In the last cycle, for example, there were no winners. This is run by Kyoto Animation.