If you’re up to date on the ins and outs of various Hollywood circles, you’ll know that Stephen Spielberg and George Lucas have been friends for many years. Spielberg directed the first couple of Indiana Jones movies in the 1980s. Before this, he directed E.T. Due to the friendship between the two directors, Lucas placed the E.T. species into Star Wars Episode I: The Phantom Menace.
Lucas even gave the E.T. species a name; the Asogians. The species in Legends did have a homeworld called Brodo Asogi. However, it is no longer canon. The reason the E.T. alien was included in Star Wars was it was a thank you from George to Stephen for directing the first three films. Spielberg would later direct the fourth film, Indiana Jones and the Kingdom of the Crystal Skull, which dropped in 2008. However, he has no involvement in the fifth film, The Dial of Destiny.
There is no information on the alien outside of them being around in the final years of the Galactic Republic. Therefore, outside of The Phantom Menace, the E.T. alien appeared in the (canon) second issue of the War of the Bounty Hunter comic series.
In conclusion, George’s gesture was nice to include E.T. in at least one of his Star Wars movies. Moreover, the Indiana Jones films have had plenty of small Star Wars references over the four released films. One is a carving of R2-D2 and C-3PO.