I had one strategy that was a "helicopter rush" to science victory in one city challenge. The helicopter rush would win domination if I was significantly ahead in tech, otherwise, it would simply pillage all of my opponents hexes. One of the key points of it was that it was hilarious! The reason to do it over mech rush was that it gave hydro plant and research lab, which enables a big production boost and ~50% more beakers per turn. Aluminum is generally accessible either in capital's 5hex radius, or else in a city state's possession. If not available, curse luck, bunker up w/ Mechs and science vic.
The helicopters would come out around turn 160. It probably wouldn't be as effective now, since Modern era techs cost more than they used to, so I would have to make it a more basic Mech Infantry rush. I found that this rush was safer than a rifle rush, which frequently failed due to oligarchy and other defender advantages.
In current CiV, I think rifle rush takes on increasing importance for both offense and defense, because of the huge oligarchy nerf. I believe Rifling is a required tech now, cannons+oligarchy+a couple other units have much more trouble defending vs rifles.
Playing with no barbarians is a completely different game from with barbarians as well. With no barbarians, longer settler travel times are allowable, to settle on distant luxuries. Temporarily skimping on military to create further economic advantage is possible. Travelling across the map to invade an opponent while leaving no troops at home to protect against barbarians is also possible. This causes a need for a faster race, with more gambles, either for military and a quick rush, or for a quick econ.
Personally, I prefer barbarians. CiV simply feels hollow without them.
Barbarians are harder nowadays too; soloing a barbarian encampment with a warrior is now only possible on plains/marsh, and is extremely risky/ill-advised on rough terrain. This is because the barbarians used to re-fortify every other turn, switching between 25% and 50% fortify. Now they stay at 50%, always. This means that the 2nd unit is sometimes required, even before turn 11.
The funny thing is that despite many of my strategies being peaceful econ strategies, everyone labels me an aggressive warmonger because I believe in unit efficiency

It is inefficient to build a unit if it is not going to be used!