Three groups without a single character capable of casting a single offensive spell? That is impressive. How did it go? So all casters took nothing but information gathering and skill buff spells?
I apologize, it's technically two groups. I'd forgotten about the wizard in the third party because he's missed about half the sessions.
That said, the first party consisted of a Totem Barbarian, a Vengeance Paladin, and a pair of warrior NPC henchmen. (There was technically also a Thief Rogue, but he was only there for a handful of sessions.) The party went from level 3 to somewhere around 8th level. While my paladin did use smite, it was the vanilla class-ability variety, so I don't consider him an offensive caster. Aside from that, he mostly used the occasional healing spell when needed. This party did quite well, faring better against smaller groups of powerful creatures than against large groups of weak creatures. The Paladin died when we ran afoul of a pack of gnolls. We realized early on that we weren't likely to win, so the paladin held them back while the rest of the party escaped. To replace him I brought in a wizard, at which point the party ceased to lack caster offense.
The second party consisted of a Battlemaster Fighter, a Shadow Monk, a pair of warrior-type henchmen, and an NPC rogue. They ran from around 9th level to level 19, although around 18th level an NPC cleric joined the party at which point they ceased to completely lack for offensive magic. This was actually one of the best campaigns I've ever run. They often had to come up with really creative solutions to problems because neither of them wanted to carry a ranged weapon. One time that they were fighting an Efreeti boss the monk ran up the side of the wall and stunned him while the fighter lassoed the boss and tried to drag him down. They comported themselves quite well, taking on threats well above double deadly.
The third party, which only counts about half the time, is an Underdark campaign that started out with a largely evil party. Thanks to a Deck of Many Things and the unlikely draw of the Balance card by multiple players, we're now a good party. This is a really big party, but suffice it to say that when the wizard is not around the most potent spellcaster in the party is my Arcane Trickster. Since I focus on defensive and utility magic, I am not in any way an offensive caster. For the sake of transparency, I should mention that I do have the Chill Touch cantrip, but I'm 99% sure I haven't actually used it since the start of the campaign. I can also cast a few druid spells due to a run-in with a lake of quicksilver sent from the heavens, but thanks to my whopping 10 Wisdom I assiduously avoid any spells that are even remotely offensive. We started at 3rd level and I'm currently 9th. Again, we do quite well. We've won at least one fight that I'm fairly certain was over 400% deadly.