I could see an Elbaf astronomer.
Pretty confident that the giant beanstalk Giant Jack was in fact a pop green planted not by a human but a giant – a vintage Oda switcheroo. It was probably this same giant that introduced Skypeians to the existence of soil and agriculture, as well as the deity known as Vearth ( or inspiring its legend in fact ).
All but positive Vearth there is based on a giant of Oars variety or something highly tied to his race. Probably a fellow Titan, if not the One Piece equivalent of classic Earth goddess and Titan Gaia.
And this theoretical One Piece Jack? Probably an Oars giant that climbed said beanstalk to do this:
Another intriguing point of interest if Waipa's mask and its own striking resemblance to Oars-related giants. Makes one wonder if the Shandorians and the Skypeians ironically shared the same deity the whole time they were fighting ( amongst other things ). Just another of many hints to the importance of Oars' race to the story.
Anyways, I could see some oni or Elbaf Giant being inspired by legends and/or history to attempt a much more ambitious ascent into space. Could be potential candidate for membership, or perhaps instead playing a similar role as Montblanc Cricket in helping the Strawhats reach new heights.
All that said, while I don't believe One Piece is ending as soon as some think ( even before Covid19 hit ), I do think Elbaf is most likely to be the 2nd or 3rd last stop before Raftel, perhaps even segueing directly into Lodestar and a sidetrip to the Moon all in the same arc; in which case, any such potential character will probably need to be introduced pretty soon to develop properly. But yeah, if any giants with an interest in tinkering with telescopes, giant beanstalks, or suspiciously gigantic fireworks/rockets were to appear next arc leading up to Elbaf…chances are sky high.