I whole heartedly believe that if a DM feels that they themselves need to pick what the caster summons, then they are showing their own bias and fear of what the player might pick. The point is to provide a fun and exciting story and power fantasy to the players. If a DM wishes to pick for the caster, then they should ban the spell, and if they would ban a spell then it shows a flaw in their ability to run a successful game.

I have the stance in my games that if it is in the book you can use it, no questions asked. If you surprise me with a powerful combination I applaud it, and you are allowed to thrive and enjoy.

Its a game, let your players have fun.

FYI to all players, if you choose 8 summoned creatures, this might really annoy your DM.

Also agreed. In spells like the ones where you summon demons the spell descriptions are very specific in stating that the DM chooses the creatures summoned, and that the caster only gets to choose the CR. No other summoning spells in the game have any such specifics in their description showing that RAW and RAI meet up neatly to say that the caster chooses the specific creatures summoned.

My DM just whipped this spell out on us and here's the scenario: I had cast levitate and is holding the baddie off the ground, not able to push off anything at convenient melee height. Our ranger centers a fog cloud above her just enough to cover the upper half of her body so she's blinded, everyone starts attacking with advantage. Since the area is heavily obscured, the only point the baddie can "see" is directly in front of her eyeballs, so that's where 8 cows appear. Yes, cows. She couldn't see far enough to weaponized the cows as cow meteors, but instead like a dog releasing turds, just a string of cows...

This is the most multi-biome purpose spell

Underwater? Sharks and octopuses

In a forest? Wolves all around

Tundra? Polar bear

Air? Swarm of giant owls please

I find it interesting that Wildshape is restricted to only animals you've seen...
But here you can summon 1-8 beasts even if you've never seen or heard of them, excellent tool to "expand" ones wildshape options list.

Quote from SabreRunner >>

Quote from Retribune >>

The player has the choice of animals within the guidelines of the challenge rating. The examples they list are actually really good as I had a player use the Saber-Toothed Tiger plenty of times.

 What about the fact that the spell states the player only chooses the challenge rating? Did you read the article as of late?

My character lived underground, so she only uses it to conjure burrowing/underground animals. Animals other than that are unfamiliar and exotic. Never let rules lawyering get in the way of flavour/RP.

Quote from Wraethrax >>

FYI to all players, if you choose 8 summoned creatures, this might really annoy your DM.

 

 

Beyond 20

 

 

 

 

 

"Roll initiative for the summoned creatures as a group, which has its own turns." 
Just restrict them to occupying no more than 2 squares and roll all 8 to-hit dice at once. Basically treat them as a single mob/swarm/pack.

People are saying that Jeremy Crawford went off the deep end and you shouldn’t trust him  

Cast at 9th level. 32 velociraptors with 2 attacks per turn each with advantage (pack tactics)
64 attacks with advantage.

Clever girls!

Quote from Daniel0 >>

Quote from Utsu_Yami >>

Would you say that this spell could be used to help with Wild Shape druid learn new animals?

 

Druid " I summon a black bear"

Studies the Bear for an hour

Druid " I can now be a Black Bear.

 My DM said no, because these animals are technically fey creatures and not actually the natural animals... And I had to agree with'em on that.

 But the reason they are taking the form of beasts is because they are spirits of nature, they'd be a perfect copy. The druid that summoned them might be able to learn more from them than from a random beast.

Whether or not you let players choose the animals (I say yes because summon lesser demons specifies that the DM decides which demons) 
I think that some creatures are way better options than others and it's probably okay to treat them as being higher CR,
it also helps keep the spell from slowing down the game.
Wolves, giant wolf spiders, and giant owls are great with this spell, I treat them as CR 1/2 with the spell but give them +4 hp and +1 to attack and damage to help. 
Panthers, giant bats, giant frogs (restrain), and giant lizards are fringe, and could reasonably deserve the same or similar.
Giant poisonous snakes might as well be CR 1/2, it's kind of weird that they aren't, they're fully as dangerous as a giant wasp but cant fly.
Black bears are decent, don't need to be changed, you could still rule you'd prefer brown bears to roll fewer attacks. 
Giant octopus are very sturdy, fast, stealthy, and have a strong restrain and an ink spray if things go badly. 
Instead of reducing the number of octupus, I make its hp 40, lower tentacle damage from 2d6+3 to 2d4+3, and add a 2d6+3 bite attack that it can use on what it's grappling.
I've made some homebrew animals, mostly crocodilians. Bull Crocodile, Marine Crocodile, and Crocozard.  There's also a Bladed Ape that resists slashing damage, and Giant Ant Soldiers. For CR2 I made the intelligent Giant Wolf. 

give them more than one option

Heheheha

What doesn't make sense to me with the idea that the GM chooses, is that it means that your character is casting a spell and doesn't know the outcome, as if they don't understand the magic they are using.  I am playing a shepherd druid, who literally have a class feature called mighty summoner, who seemingly wouldn't be able to conjure what he wants.  Seemingly forces your character to seem incompetent when they cast this.

Exactly because some spells explain specifically what you can summon, and this doesn't, shows that the caster can choose, when the DM have to choose it's generally written. Furthermore, magic is really rare to be randomic so it's obvious that the player has to choose what to summon and not the DM.

My DM said no because if I'm choosing what they look like then I need to know what the thing I'm summoning is

i think it's better to let the players choose  i mean take polymorph into consideration it doesn't clearly say but pretty much everyone agrees it's the players choice and it cuts down on the time it takes to cast the spell it's just easier since the player should already know what they're going to summon while if the dm chooses they have to go searching for a creature that qualifies

btw you can use this to summon 8 riding horses for an hour

If the DM allows you to pick the creatures being conjured, can you assume that you could also ride them, for example, horses for your party?