Oscillator modules produce repetitive (audio or modulation) signals. The rate of the repetition (frequency) determines the pitch while the loudness is controlled by the amplitude.  The timbre is determined by the shape of the oscillator.
Overtones:

va100HzSin spectra

Sine: just the fundamental, no overtones.

va100HzTri spectra

Tri: just odd, weak overtones.

va100HzSaw spectra

saw: many overtones.

va100HzPulse012 spectra an

pulse: harmonics depend on pulsewidth.

Hard Synchronization:
Everytime the waveform of the master osc starts, the slaveOsc restarts accordingly.
Sync master oscillators: multiOscSyM, uknowSyM.
SyncSlave oscillators: modulationSynthesisOsc, MultiSyncS, uknowSyS, pulseSyncS, sawSyncS, sineSyncS, AliasawSimpleSync, NBLaliasawSync, NBLsawSync.
The SyncS OSCs can also be restarted by using the Gate2Sync module.

HardSync_sawMaster

sync master (saw)

HardSync_sine-5

sync slave
(sine -5)

HardSync_sine+7

sync slave
(sine +7)

Soft Synchronization:
can be achieved by using the Flexor3 SoftSync module. It reverses the phase of the slave osc acc. to the master osc’s polarity by using FM.

SoftSync

dspLoad 2,50/5.60/2.50          Poly16

SoftSync_sawDry

sync master (saw)

SoftSync_saw-5

sync slave
(saw -5)

SoftSync_saw+7

sync slave
(saw +7)

Overview Flexor oscillators:
while Creamware, SpaceF and Zarg oscs use  the same sdk dsp atoms/waveforms, Flexor modules have a different design.

sawCW-sawFlex

In addition, Flexor provides numerous  shapers to alter the osc waveform in many ways, e.g.:

FlexSaw2PWM-GuitarDr

OSC overview
CzOscs

ModulationOSCs
MultiOSCs
NoiseOSCs
PulseOSCs
SampleOSCs
SawOSCs
SawOSCsFlexor
SineOSCs
SpecialOSCs
Spectral&MorphOSCs
TubeResonator
WaldorfOSC
WavetableOSC
UknowOSCs

SpaceF_OSCs
ZargOSCs