Which spells are best for druids in D&D (5E), below level 8?

It all depends on how you play your Druid. Moon Druids will spend a lot of time in combat and beast form so that concentration spells won’t last long. You also won’t have an extremely high AC and can’t cast in Beast form. Out-of-combat spells would be better and provide you with more versatility. There are many options.
If you don’t, you can still make some great choices. However, many of these options are situational, so it is good to have a variety.

What is the best? Which is better: damage, control, buffing allies or summoning creatures that can do some damage but not too much? Which of the 4th-level spells would you recommend? The stone shape is not good for combat, but it can be very useful in certain situations. The same applies to all levels below.
Level 8 gives you access to level 4 spells. Below, I have compiled a list of spells that I have personally found very useful as druids.

A druid can be useful to control the battlefield, summon and heal PCs.
They are not primary damage dealers and are not a front-line combat PC.
Outdoor combats are essential to make the Druid shine. That is because the combatants must see each other at ranges of 300 to 1200 feet. Combat doesn’t always begin with the PCs being able to close in mele their first turn.

1st Level – Goodberry 5e

You want to be the most important member of the team during a survival situation. Get Goodberry! You can feed everyone with just one 1st-level spell slot per day. It is not enough to heal.

DND Spells GIF from Dnd GIFs

Goodberry 5e

Level 1 transmutation

Casting Time: 1 action
Range: Touch

Components: V S M (A sprig of mistletoe)
Duration: Instantaneous
Classes: Druid, Ranger

Up to ten berries seem in your hand and are infused with magic for the duration. A creature may use its action to eat one berry. Eating a berry heals one hit point, and the berry provides enough nurture to sustain a creature for one day.
The berries lose their strength if they have not been consumed within 24 hours of casting this spell.

Moonbeam 5e – 2nd Level

It rains radiant death and glory from the heavens every turn. You can move the beam and block most corridors with a radius of 5ft.

Moonbeam 5e

Level 2 evocation

Casting Time: 1 action
Range: 120 feet

Components: V S M (Several seeds of any moonseed plant and a piece of opalescent feldspar)
Duration: Up to 1 minute
Classes: Druid

A silvery beam of pale light radiates down in a 5-foot-radius, 40-foot-high cylinder centered on a point within range. Until the spell ends, dim light fills the cylinder.
When a creature enters the spell’s area for the first time on a turn or starts its turn there, it is engulfed in ghostly flames that cause searing pain, and it must make a Constitution saving throw. It takes 2d10 radiant damage on a failed to save, or half as much damage on a successful one.
A shapechanger makes its saving throw with disadvantage. Suppose it fails. It also immediately reverts to its original form and can’t assume a different form until it leaves the spell’s light.

After you cast this spell on each of your turns, you may use an action to move the beam 60 feet in any direction.
At Higher Levels. Suppose you cast the spell using a spell slot of 3rd level or higher. The damage increases by 1d10 for each slot level above 2nd.

3rd Level: Conjure Animals 5e

Have you ever needed a step-ladder for your home? You can conjure up eight mules to help you climb a steep hill. Do you ever need to be distracted? To create chaos, gather eight wolves. Do you want to fly in style? Two Giant Eagles can be conjured. Although the DM can choose the creature that spawns, I have always chosen the best in all I have played. I also let the players choose the best in every campaign I have DMD.

Dnd GIF from Dnd GIFs

Conjure Animals 5e

Level 3 conjuration

Casting Time: 1 action

Range: 60 feet
Components: V S
Duration: Up to 1-hour Concentration

Classes: Druid, Ranger
You summon fey spirits that take the style of beasts and appear in unoccupied spaces that you can see within range. Please choose one of the following options for what appears: One beast of challenge rating 2 or feebler Two beasts of challenge rating 1 or lower Four beasts of challenge rating 1/2 or lower Eight beasts of challenge rating 1/4 or lower Each beast is also considered fey. It disappears when it drops to 0 hit points or when the spell ends. The charged creatures are friendly to you and your companions. Roll initiative for the summoned creatures as a gathering, which has its turns. They obey any verbal commands that you issue to them (no action required by you). If you don’t issue any commands, they defend themselves from unfriendly creatures but otherwise take no actions. The GM has the creatures’ statistics.
At Higher Levels: When you cast this spell using certain higher-level Spell Slots, you choose one of the summoning options above, and more beasts appear – twice as many with a 5th-level slot, three times as several with a 7th-level slot, and four times as many with a 9th-level slot.

Polymorph 5e – 4th Level

You may get tired of being able only to transform into horrible creatures that don’t do any damage if you are a non-moon druid. Imagine if I said you could turn into a Giant Ape to teach others how powerful beasts can be. It’s a great way to increase your damage and indulge yourself, Moon Druids. You can also turn your enemies into turtles if you wish.

Polymorph

Level Four transmutation

Casting Time: 1 action

Range: 60 feet
Components: V S M (A caterpillar cocoon)
Duration: Concentration, Up to 1 hour

Classes: Bard, Druid, Sorcerer, Wizard
This spell changes a creature that you can see within range into a new form. An indifferent creature must make a Wisdom saving throw to avoid the effect. The spell does not affect a shapechanger or a creature with 0 hit points.
The transformation lasts for the duration or until the target drops to 0 hit points or dies. The new form can be any beast whose challenge rating is equal to or less than the target’s (or the target’s level, if it doesn’t have a challenge rating). The target’s game stats, including mental ability scores, are replaced by the statistics of the chosen beast. It retains its alignment and personality.

The target assumes the hit points of its new form. When it reverts to its normal form, the creature returns to the number of hit points before it transformed. If it reverts as a result of dropping to 0 hit points, any excess damage carries over to its normal form. As long as the excess damage doesn’t reduce the creature’s normal form to 0 hit points, it isn’t knocked unconscious.
The creature is limited in its actions by the nature of its new form, and it can’t speak, cast spells, or take any other action that requires hands or speech.
The target’s gear melds into the new form. The creature can’t activate, use, wield, or otherwise benefit from any of its equipment.