Is it possible to vary an LED from low to high brightness at any frequency without MCU?
Solution 1:

Use MCU, if the key factor is only price and dimension you can still use couples of MCUs, for example attiny85. It is cheap, small and you can program to it what ever sequence of flashing, dimming or changing brightens you want.

Solution 2:

If still for what ever reason you want to stick to analog design you can use 555 timer to get desired functionality. Here is the link for your demand:
555 Pulse Generator Circuit