New styles sit at the end of each metric's list in the Gauges tab. Pick the metric first; the style follows it.

Neon works with any numeric metric: a big glowing number that changes colour as the value climbs. Flame bar is a fat bar that shifts colour and throws fire off its tip, growing with the value. Streak puts speed lines behind the number — more, longer and faster as you speed up.
Speedo is a full dial with a needle that swings from its hub across a printed scale, with the digital value below. Pick it under Power or Heart rate instead of Speed and the needle and scale follow that metric.
Ride (with Speed) is a bike whose wheels turn with your speed and whose crank turns with your cadence.
Spinner (with Cadence) is a drivetrain whose chainring and cog turn with your pedalling.
Pulse is a glossy heart that beats at your real heart rate. Heartbeat is a zone-coloured ring around a beating heart.
Terrain (with Slope) tilts an arrow with the road, colours the number from green to red as it gets steeper, and paints the elevation profile by gradient. Vertical speed is new too.

Build your own look with the new Effects, on any element: colour that changes with the value (cool to hot, neon, fire, heart-rate zones), glow, a faint echo trail, and a flame on bars that lights once you pass the point you choose. Dials can print their scale numbers: switch on Numbers on a Ticks element and it prints the same range the needle uses.

Nine ready-made gauges with life in them: a beating heart, a real speedometer, a bike with turning wheels, and fire on the speed bar.