With June's arrival, we're racing toward the halfway mark of 2023 -- and valuations for growth stocks have also generally been racing higher. The growth-heavy Nasdaq Composite index has now climbed 25% year to date, but there are still top tech companies trading at levels that leave room for investors to see explosive gains over the long term. Following its initial public offering in March 2021, Roblox (NYSE: RBLX) stock went on to hit a lifetime high of nearly $135 per share in November of that year as pandemic-related conditions helped the company record stellar engagement and bookings growth.