Eyepieces are an easy way to get more from a telescope, and a Barlow lens doubles what you have. A Moon filter tames lunar glare, but it is not a solar filter: for the Sun, read solar filters first, which follows NASA and AAS safety rules. Red lights, finders, star charts and power are in astronomy accessories, and NASA's advice on binoculars is in binoculars for astronomy.
Gear guides
The eyepiece math in plain terms, and Celestron and SVBONY eyepieces and kits compared by listing.
How a Barlow works, the useful-magnification catch, and 2x Barlows compared by listing.
Fixed, variable and ND Moon filters compared by listing, with the solar safety warning.
NASA and AAS solar safety rules, and front-mounted solar filters from AAS-listed makers.
Red lights, finders, star charts, phone adapters and power for telescopes, compared by listing.
NASA's advice on astronomy binoculars, and handheld and tripod-mounted pairs compared by listing.