Golion's main five characters are obviously followed by Voltes V and Combattler V, all three were combining robot shows based on five mecha.
This was also clearly copied from Gatchaman as well. Even the personalities are pretty close. All three teams had their base that was actually secretly flying mecha. For Voltes V and Golion, both of them invaded their enemy planets to liberate the people from their respective dictators.
Professor Raible was obviously based on professors of the past.
Raible is similar to Dr. Nambara, Dr. Yotsuya, Dr. Hamaguchi and Dr. Sakunji in Voltes V. Also Bertha from Daimos had a Golion counterpart in Hys who sadly died.
Emperor Daibazaal and Emperor Zanbazil were both supreme dictators and cowards at best.
They have combat skills and hid behind their armed forces. They can turn cowardly when the tables are turned on them while relying on scapegoats to take the blame for their failures. They were both ruthless even to their own subordinates treating them all like trash and as convenient scapegoats. For Daibazaal, the plot of being the illegitimate child of the previous emperor was obviously copied from Zanbazil. How Daibazaal ascended the throne of Galra and turned it into an absolute dictatorship is unknown, Zanbazil's story was more detailed and explained to how he became emperor except we know nothing about his mother, we later discover that Daibazaal is the illegitimate son of the previous emperor and Honerva (but he never referred to her as such as treated her like trash). The Galrans also used the skull symbolism prevalent of the Boazan and the Campbells in Voltes V and Combattler V. The most obvious has to be the beast fighter launching against the enemy.
Both shows had adversaries in the form of a prince that worked for their respective emperors.
Both Sincline and Heinel were more focused on one-on-one tactics than using dirty tactics though neither would hesitate to do so as long as it's under their command, that is, "I'm the only one allowed to defeat you." Sincline had a hatred for Akira and for Heinel to Kenichi. Other than that, the two are different execution-wise. Just my thoughts- Heinel is way better than Sincline considering that hey at least, the former has better plans than Sincline's lust for Farla isn't really working itself out! Heinel was however hinted as the only last possible heir to Zanbazil considering the fact he's the only legitimate heir known since his father was adopted by his granduncle while Sincline is the son of Daibazaal and an Altean woman. Hmmm... Voltes V had the three Go brothers as half-Boazan, half-human. A play around plot of half-breeds?
Honerva was a witch like Empress Janera from Combattler V both skilled in witchcraft.
Both of them were mistresses of deceit and had an unnatural cruelty towards their opponents. In the case of Honerva, it was a last minute plot that revealed that she was the previous emperor's mistress and that Daibazaal was her illegitimate son, making her the grandmother of Sincline though neither felt any attachment to each other. I still think though Janera is more competent than Honerva can be.