Look like modified hitch pins
1”
https://www.amazon.com/dp/B07X51W43G/ref=cm_sw_r_cp_api_glt_fabc_EHN92NMD08TYT3SHCMHV
5/8”
https://www.amazon.com/dp/B082ZK6XDR/ref=cm_sw_r_cp_api_glt_fabc_YETDAJC50DB3WV147ERC
https://www.harborfreight.com/58-in-easy-grip-hitch-pin-63671.html
Assuming 5/8" is ok.
https://www.amazon.com/CURT-45803-1-Inch-Clevis-Rubber-Coated/dp/B07X51W43G/ref=pb_allspark_session_sims_desktop_86_1/144-0526974-7634543
1"