| BNR Prolog | ⊕ 1985 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ Canada | |
| C-Prolog | ⊕ 1985 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ United Kingdom | |
| Edinburgh Prolog | ⊕ 1985 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ United Kingdom | |
| Modula-Prolog | ⊕ 1985 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ Switzerland | |
| N-Prolog | ⊕ 1985 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ United Kingdom | |
| Prolog-ELF | ⊕ 1985 | ↓ ↑ ⊕ Experimental and other | ⊕ Horn clause | ⊕ Japan |