Updated with natures from this paste by gifvex: http://pastebin.com/raw/Ze5dxJia
(Other relevant paste: http://pastebin.com/raw/dFgtxdUs)

Croconaw

PRE-PURIFICATION
39: Hoothoot
40: Ledyba, Kirlia
41: Barboach
42: Horsea, Remoraid
43: Barboach
45: Meditite, Goldeen
46: Vulpix, Surskit, Carvanha
47: Natu, Baltoy
49: Carvanha

POST-PURIFICATION
- Claydol (0 or 4-5 ties; 20-21 or 25-27 ties if -Speed)
- Pinsir (0-2 or 4-5 ties)
- Zangoose (3-4 or 7-8 ties; 24-25 or 28-29 if -Speed)
- Blaziken (10-11 ties at L49)
- Gardevoir (14-15 ties at L49; 10-11 ties at L50; 7-8 ties with Carbos at L50)
- Altaria (13-15 ties)
- Delcatty (15-16 or 19-21 ties)
- Vigoroth (16-18 or 22-24 ties)
- Sharpedo (20-21 or 24-25 ties)
- Linoone (31 ties at L40; 14-15 or 20-21 ties if +Speed)
- Voltorbs (20-21 +Speed or 26-28 +Speed ties) 

--------------------
Espeon

- Linoone (8-10 Quiet ties)
- Voltorb (12-13 Quiet or 21-22 Quiet ties)
- Swellow (17-18 Quiet ties)
- Yanma (26-28 Quiet ties)
- Starmie (4-5 ties at L52 (6 if no Jumpluff EVs); 26-27 Quiet ties at L53) 
- Electrode (11-12 ties)
- Electrode (14-15 ties)
- Ludicolo in rain (27-29 ties)