As I began working more and more with analog synths, I've really found it nice to have analog LFOs that are synced to my MIDI sequencer.  .  At first, I used to try to input my own modulation with my MIDI controller, and use the control voltage  output from my MIDI to CV converter.  I quickly realized that this taxes the MIDI chain very heavily, and I needed a new method.

I have several drum machines in my collection, so I use one of them as a "clock source".  Basically, I tap in a drum pattern  at the speed I want the LFO (16th notes, 8th notes, etc).  I usually use a quick decaying sound like a "click" or "tic" sound.  I run this sound through an unused output on the drum machine, and into a Envelope Follower & Comparator to create a trigger pulse.  This trigger can be used as a clock input to your analog sequencers to keep them in time with your MIDI signals.   You could also use the Envelope Follower output to trigger things like an analog drum sound.

f you need a different type of LFO shape, you have several options.  First, you can run the trigger from your Envelope Follower output to the input on an Envelope Generator.  You can then use the envelope generator to create many waveforms by adjusting the A, D, S and R values on the Envelope Generator..

Using a Slew Rate Limiter(glide or portamento circuit) on the Envelope Follower output can produce some interesting results.   When using a linear glide circuit, the output  will resemble a saw wave with slewing on one direction or a triangle wave with slewing in both directions. You can adjust the "pulse width" or more correctly, slope by changing the portamento time.  Using exponential glide circuits would provide yet another wave shape.

If you have analog LFOs with a "sync" input, you can simply use your Envelope Follower output to drive them.   If the speed of the analog LFO and the MIDI "tic" are close to each other, you'll get a nice hard sync.  If you vary the rates, the LFO will create some interesting rhythmic beating. You just need to check if you need a positive or negative pulse to reset your LFO, and invert your gate if required.