I can't recall seeing a single buff spell above 4th level. And there's a lot of filler.
They're there. Remember all casters have fewer higher level spells across the board in this version of the game. But for the 4th level and above, we have:
Freedom of Movement – unaffected by difficult terrain, speed reduction, paralysis, or restraint, can escape from nomagical restrains, freely move underwater.
Polymorph – definitely can be a buff, particular in that it essentially boosts your hit points during those rounds.
Regenerate – cast before a battle, it’s a buff.
Foresight – immune to surprise, advantage on all attack rolls, ability checks, and saves. Other creatures have disadvantage on attack rolls against target as well.
True Polymorph - can be a buff, depending on what you turn someone into.
There are lots of other spells that are more subtle in the way they help the party, but which have essentially the same net effect as a buff. For instance, Guards and Wards protects (essentially) against wandering monsters interrupting a rest, and can be a strong advantage for a raid on a building if the party prepares in advance for the things it does to various corridors while those inside the building were not prepared. Symbol has a similar effect. Some other spells help with distance communication (Dreaming), or serve to help the entire party bypass a threat through a mass illusion (seeming). Again, not direct buffs, but the net effect of these spells, used well, can serve the same end result.
And there's some bard spells for 3e that are missing like song of discord, shout or nightmare.
Nightmare is Dream now. Song of Discord is mostly Crown of Madness now.
And other bard spells like grease, glitterdust, summon monsters, shadow evocation/conjuration, geas, heroes feast, veil or seeming, haste and slow.
A bunch of those are there. Glitterdust is Faerie Fire. Veil is Seeming or any of several illusion spells, depending on your use. Geas and Seeming are there. Grease, Summon Monsters, Shadow conjuration/evocation, Heroes Feat, and Haste/Slow are indeed missing. Consistent with all those spells, they've removed most of the physical conjuration spells from the Bard, and focused it more mind and illusion.