| coq | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ France | ||
| M-LISP | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ Lazy Evaluation LISPs | ⊕ United States | |
| Neuro-Prolog | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ Japan | |
| Neuro-Prolog II | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ Japan | |
| NUA-Prolog | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ United Kingdom | Extension to the WAM for Parallel Andorra |
| NUE-Prolog | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ Australia | |
| Quintec Prolog | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ United Kingdom | |
| R-Prolog | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ||
| STARSIM | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ United States | Simulator for *Lisp | |
| WCL | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ Lazy Evaluation LISPs | ⊕ United States | CLX optimised for multiple programs |