The top five effects for beginning guitarists (in my opinion everyone may not agree on all of these, but those differences make us better together and cause us to re-think our opinions in our never ending chase for the “perfect tone”) are:

EQ – An Equalizer will do amazing things for your sound. I added a MXR 10 band EQ (in pedal form) to my rig and I couldn’t believe how much it cleaned up my sound and made my sound much more focused. I have several EQs in my pedal board, both graphic and parametric.

From Sweetwater: ”A graphic EQ is designed to cut or boost level on equally spaced frequencies, such as 1/3-octave or octave spacing, with a preset bandwidth value. Parametric EQ, on the other hand, gives you fewer EQ bands, but with more control, letting you vary the center frequency of the boost or cut, as well as the bandwidth of the adjustment.” https://www.sweetwater.com/insync/should-i-use-graphic-or-parametric-eq/ I also have a DBX 31 band graphic EQ as part of my analog rack of effects.

Overdrive – Is an effect that mimics the sound of a tube amp binging driven or over driven to add a pleasing amount of harmonic distortion to the guitar sound. Being able to change from a clean sound to a nicely distorted sound is absolutely necessary. I have, and usually use two different overdrives that I can choose between the two because they each sound different and/or use both together (stacked) for a much more distorted sound.

Delay – echo and other time-based effects are great! I tend to use a subtle delay instead of reverb. And a heavy amount of delay is great to use to “swell” into (heavy delay, then hit a chord with the volume off either with the knob on the guitar or a volume or expression pedal and simply bring the volume up).

Compression – This effect will bring your load parts down a bit and the softer volume parts up a bit, thereby smoothing out your dynamics or volume.

Again, from Sweetwater…
“A compressor is a device that reduces the dynamic range of an audio signal. First a threshold is established. When the audio signal is louder than this threshold, its gain is reduced. The amount of gain reduction applied depends on the compression ratio setting. For example, with a 2:1 ratio, for every 2 decibels the input signal increases, the output is allowed to increase only 1 decibel. A variety of other parameters in the compressor will also affect its performance processing specific signals; attack time, release time and others are very important. There are a variety of uses and applications for compressors, the most obvious one being to control the dynamic range of a live performance so that it will fit into the fairly narrow dynamic range of recorders, etc. Other applications include making a signal’s average level higher, increasing the apparent sustain on a guitar, evening out a vocal or bass guitar performance, fattening up sounds, and on and on. The list of possibilities is extensive!” https://www.sweetwater.com/insync/compressor/

Chorus – This effect is accomplished by taking the original signal coming in and splitting it into two signals. Then taking one of the signals and delaying it very slightly (maybe 20 milliseconds or so) and then combining the two signals back together just before sending the signal to the output of the effect. The result is a “thickening” of the sound. You can use this effect either very subtly or more in your face out front style. This effect was a hallmark sound of the 80’s and 90’s clean sounds.

This is one of my favorite effects, having gigged a lot during the 80’s and 90’s. I have several different choruses in my pedal board and a vintage Tri-stereo chorus in my rack. So, I have to be VERY careful NOT to overuse it.