III - Dire Boar

LG Large animal
Str
23
Dex
10
Con
17
Int
2
Wis
13
Cha
8
Race
Dire Boar
Celestial
Resolute
Senses
Darkvision 60ft
Low-light vision
Scent
Speed
40 ft

  • 45 HP 5 animal: 5 class, 3 con, 1 feat
    DR 5/evil or chaotic. Resist 10 acid, cold, electricity, fire.
    Ferocity — Fight until death.
  • 15 AC touch 9, flat-footed 15 10, 0 dex, -1 size, 6 natural
  • 7 Fort 3 con, 4 class
  • 4 Ref 0 dex, 4 class
  • 2 Will 1 wis, 1 class
  • SR 10
  • 10 CMB; 20 CMD 3 bab, 6 str, 0 dex, 1 size

Natural Attacks 20×2

Gore +8 vs AC 3 bab, 6 str, -1 size 2d6+9 P  
Smite Evil/Chaos — 1/day, mark an evil or chaotic foe. Add 0 cha to hit and 5 hd to damage. Bypass DR.

III - Leopard

LG Medium animal
Str
16
Dex
19
Con
15
Int
2
Wis
13
Cha
6
Race
Leopard
Celestial
Resolute
Senses
Darkvision 60ft
Low-light vision
Scent
Speed
30 ft
Climb 20 ft

  • 21 HP 3 animal: 5 class, 2 con
    Resist 5 acid, cold, electricity, fire.
  • 15 AC touch 14, flat-footed 11 10, 4 dex, 1 natural
  • 5 Fort 2 con, 3 class
  • 7 Ref 4 dex, 3 class
  • 2 Will 1 wis, 1 class
  • SR 7
  • 5 CMB; 19 CMD 2 bab, 3 str, 4 dex +4 to grapple!

Natural Attacks 20×2

Bite +6 vs AC 2 bab, 4 dex 1d6+3 BPS Grapple as a safe free action.
Claws +6/+6 vs AC 1d3+3 BS  
Smite Evil/Chaos — 1/day, mark an evil or chaotic foe. Add 0 cha to hit and 3 hd to damage. Bypass DR.
Pounce — Can full attack at the end of a charge.
Rake — Gain 2 bonus claw attacks vs grappled foes.

Lantern Archons are also good candidates for summon monster III.

IV - Tiger

LG Large animal
Str
23
Dex
15
Con
17
Int
2
Wis
12
Cha
6
Race
Tiger
Celestial
Resolute
Senses
Darkvision 60ft
Low-light vision
Scent
Speed
40 ft

  • 48 HP 6 animal: 5 class, 3 con
    DR 5/evil or chaotic. Resist 10 acid, cold, electricity, fire.
  • 14 AC touch 11, flat-footed 12 10, 2 dex, -1 size, 3 natural
  • 8 Fort 3 con, 5 class
  • 7 Ref 2 dex, 5 class
  • 3 Will 1 wis, 2 class
  • SR 10
  • 11 CMB; 23 CMD 4 bab, 6 str, 2 dex, 1 size +4 to grapple!

Natural Attacks 20×2

Bite +9 vs AC 4 bab, 6 str, -1 size 2d6+6 BPS Grapple as a safe free action.
Claws +10/+10 vs AC 1d8+6 BS Grapple as a safe free action.
Smite Evil/Chaos — 1/day, mark an evil or chaotic foe. Add 0 cha to hit and 6 hd to damage. Bypass DR.
Pounce — Can full attack at the end of a charge.
Rake — Gain 2 bonus claw attacks vs grappled foes.

Hound Archons are also good candidates for summon monster IV.

V - Ankylosaurus

LG Huge animal
Str
31 27, 4
Dex
10
Con
21 17, 4
Int
2
Wis
13
Cha
8
Race
Ankylosaurus
Celestial
Resolute
Augment Summoning
Senses
Darkvision 60ft
Low-light vision
Scent
Speed
30 ft

  • 100 HP 10 animal: 5 class, 5 con
    DR 5/evil or chaotic. Resist 10 acid, cold, electricity, fire.
  • 22 AC touch 8, flat-footed 22 10, 0 dex, -2 size, 14 natural
  • 14 Fort 5 con, 7 class, 2 feat
  • 7 Ref 0 dex, 7 class
  • 4 Will 1 wis, 3 class
  • SR 12
  • 19 CMB; 29 CMD 7 bab, 10 str, 0 dex, 2 size

Tail 20×2 S

PA -2+6
+16 vs AC 7 bab, 10 str, -2 size, 1 w.focus
3d6+15 15 str½
Reach 15ft.
On hit, foes are dazed³. Fort DC 25 negates; lasts 1d4 rounds on crit.
Smite Evil/Chaos — 1/day, mark an evil or chaotic foe. Add 0 cha to hit and 10 hd to damage. Bypass DR.

V - Dire Lion

LG Large animal
Str
29 25, 4
Dex
15
Con
21 17, 4
Int
2
Wis
12
Cha
10
Race
Dire Lion
Celestial
Resolute
Augment Summoning
Senses
Darkvision 60ft
Low-light vision
Scent
Speed
40 ft

  • 80 HP 8 animal: 5 class, 5 con
    DR 5/evil or chaotic. Resist 10 acid, cold, electricity, fire.
  • 15 AC touch 11, flat-footed 13 10, 2 dex, -1 size, 4 natural
  • 11 Fort 5 con, 6 class
  • 8 Ref 2 dex, 6 class
  • 3 Will 1 wis, 2 class
  • SR 11
  • 16 CMB; 28 CMD 6 bab, 9 str, 2 dex, 1 size +4 to grapple!

Natural Attacks 20×2

Bite +14 vs AC 6 bab, 9 str, -1 size 1d8+9 BPS Grapple as a safe free action.
Claws +15/+15 vs AC 1d6+9 BS  
Smite Evil/Chaos — 1/day, mark an evil or chaotic foe. Add 0 cha to hit and 8 hd to damage. Bypass DR.
Pounce — Can full attack at the end of a charge.
Rake — Gain 2 bonus claw attacks vs grappled foes.

Earth elementals — sometimes Air, Fire, Ice, Lightning, Water elementals — are also fine candidates for summon monster V. They have cool immunities, useful movements, and can trigger weaknesses.

Consider summoning multiple Tigers!

Consider turning your summons mythic agile: +2 dodge to AC, bonus HP, evasion, +30ft on all speeds, but mostly for Dual Initiative.