Every expression returns a value, so you can assign the result of an if/else or switch statement to a variable. Within your conditional clauses, you don't have to repeat assignments or return values. If the logic goes down that branch, then the last value in that block is the return value.
This also means you don't have to have explicit 'return' statements in functions. Whatever the last value of the last expression is, that's your function return value. You can use an explicit return if you want to exit the function early, however.
Ruby has a switch (case/when) statement. Python finally has this in 3.11 I believe, but it took forever to get.
Hash.dig(). If you have nested hashes (dicts), you can myhash.dig(:top_key, :lower_key, :even_lower_key)
In objects, you can control which attributes can be read/written via attr_reader, attr_writer, attr_accessor. So you can make an attribute have a default getter if you use attr_reader :some_attribute, and then you can write your own setter if you want to control how it gets assigned to. You can even simply not have a setter, so you can effectively make an attribute read-only.
Clean, simple hash initializers: h = Hash.new { |h, k| h[k] = { age: 0, nickname: k } }. So now you can just start assigning to values in h like h["bob"][:attr1] = 28, and now h["bob"] refers to a hash with age 28 and nickname "bob". Yes Python has defaultdict, but it's an extra thing you have to use, and it's clumsy compared to the Ruby approach.
Hash (dict) merging: It's a mess in Python. In ruby it's just h1.merge(h2), or even h1.merge(key_to_update: 123). And you get a new hash as the result. Or you can merge in place with merge!(), changing the original.
Function names with ! and ? greatly simplify function naming (and improve readability). So instead of is_foo(), you just have foo?(). And if you want to indicate that you are doing something destructive, you name it foo!(). This is a common pattern in Ruby libraries, and you often have functions which return a new value and functions with the same name followed by ! which modify the input value. String.strip() returns a new string without leading/trailing whitespace, while strip!() modifies the input string to the same effect.
Python's list comprehensions are arguably ugly and messy and harder to visually parse when reading. Ruby has consistent ways of doing operations on collections. This would take a full page to show examples.
Copying and pasting code in Python often results in new code which is indented wrong (in the wrong scope), and which you must manually fix. This is not a problem in Ruby, since there are actual 'end' statements. Editors know how to properly indent what you paste.
Safe navigation. myobj&.someattr&.foo will give you the value of foo or nil if myobj or someattr don't exist. You have to use ifs to do this in Python.
Array flattening. nested_arrays.flatten(). But in python, you have to use something like list(itertools.chain(*arr)), but that fails if the first element of the list is an int (not an iterable).
Gettings hash/dict keys. In Ruby, you just do myhash.keys and you're done. But in Python there are several ways to get the keys, none of which is as simple and obvious as just keys().
Not allowing typos to silently fail. With Python, you can take an object and assign a value to a non-existent attribute. You might do this accidentally if you have a typo when trying to set an actual attribute: myobj.first_Name = "bob". Python will happily do that, and you'll later debug and wonder why myobj.first_name == "" (and then notice that you have this similarly named attribute now called first_Name). Duh. I guess you could say it's convenient to be able to do this, but it's more a footgun. Ruby will bark at you if you try this.
List sorting in Python is in-place, so you can't non-destructively sort and get the sorted list returned. In Ruby you have a choice. sort() is non destructive, and sort!() is in-place.
I've got more, but this is enough.