a grass snake

• 983, 894, 2 (2 of 3 spawns here)
• 1138, 166, 2 (seen once)
• 1096, -231, 2 (seen once) (1 of 2 spawns here)
• 923, 312, 2 (seen once)
• 875, -480, 2 (seen once) (1 of 2 spawns here)
• 1198, 933, 2 (seen once)
• 1213, -140, 2 (seen once) (1 of 2 spawns here)
• 1078, -294, 2 (seen once)
• 829, -323, 2 (seen once) (1 of 2 spawns here)
• 820, -304, 2 (seen once)
• 692, -246, 2 (seen once)
• 885, 938, 2 (seen once)
• 825, -770, 2 (seen once)
• 1121, 612, 4 (seen once) (1 of 3 spawns here)
• 1216, -445, 4 (seen once)
• 860, 375, 2 (seen once)
• 946, 232, 2 (seen once)
• 853, -312, 2 (seen once)
• 1090, 30, 2 (seen once) (1 of 2 spawns here)
• 847, -455, 2 (seen once) (1 of 2 spawns here)
• 963, -315, 2 (seen once)
• 1155, 638, 2 (seen once) (1 of 3 spawns here)
• 1116, -124, 2 (seen once)
• 1267, 264, 2 (seen once)
• 1198, -93, 2 (seen once) (1 of 2 spawns here)
• 1275, 128, 2 (seen once) (1 of 3 spawns here)
• 1158, -90, 2 (seen once)
• 1224, -345, 2 (seen once)
• 984, -213, 2 (seen once)
• 680, -162, 2 (seen once)

As /loc gives them: Y, X, Z, the most used first; nearby spawns share a spot, and one seen in a single visit may be where the mob had been pulled to.