For the Tag, I'd recommend searching http://www.ofrei.com and seeing if they have spare links in stock or ebay:Guys, where i can find Strap links of these old watches?
Tag Heuer Professional WM 1113
AND
Omega Seamaster Recife
Thanks :3
https://www.ebay.co.uk/b/TAG-Heuer-Watch-Parts-Tools-and-Guides/173696/bn_1675343
The Omega will be more difficult, so your best bet is ebay or keeping an eye on watch auction sites (like https://www.invaluable.com/mens-omega-watches/sc-uzew8gm821/) , but I really don't think you'll be able to purchase single links for the Recife; more likely a complete strap and even then, they're very rare.