Wizard is ideal for experimentation, my goal is typically to get ALL spells on a Wizard.

Which is why I prefer to usually only have one of them, because otherwise it would get too expensive.

With Cantrips obviously you cant have all of them, but of the non-damage ones I would only go for Light or maybe True Strike; the later to make sure the next expensive highlevel spell based on an attack hits. The damage ones, well, I take Eldritch Blast on level 4 by picking Spellsniper as first feat. Other than that Acid Splash is the only area attack Cantrip (very small area though) and leaves acid on the ground, Ray of Frost slows opponents (but only a little) and freezes water surfaces (or acid on the ground), Shocking Grasp makes opponents lose their reaction, Bone Chill makes healing impossible for one turn, Fire Bolt of course can put many things on fire, and Poison Spray does the most damage but you have to get close and of course many things are immune to poison.

Ritual spells can be cast outside battle for free. Which is why its good to have them: Longstrider (cast on everyone after rest), Enhanced Leap (10 turns, good to cast on the tank right before battle starts so they can move around very quickly), Disguise Self (basically a musthave for Drow but also very useful utility), Detect Thoughts (Concentration, Int/Wis Save, so a Wizard is ideal for this).

Good spells:

- Mage Armor - nobrainer until you get gear that does the same and frees the spellslot

- Magic Missle - If everything else fails, Magic Missle always does damage

- Enlarge (Concentration) - Like a lesser version of Haste really, you give your party tank better stats by enlarging them. Note this conflicts with other Concentration spells.

- Hold Person (Concentration, Wis Save) - Uber strong when it hits, but you need to take in consideration its a Wisdom save. So its bad against most spellcasters, and Paladins.

- Misty Step - Get into safety, quite useful to have

- Haste (Concentration) - As mentioned here the Metamagic is really great to have, so you could haste two instead of just one person. But its still good even if its only one person.

- Counterspell - Really basically a musthave, destroy the opponent spells

- Animate Dead - If you go the Necromancer road, you get this spell for free, AND you get two summons, AND they are stronger.